Why do people say diamonds are not rarer than colored gemstones?

[Garry H (Cut Nut)]

Conspiracy theories about diamonds being over priced and not rare confuse me.
1. There are many more kilograms of each of Emerald, Sapphire and Ruby mined each year than diamonds.
2. The yield on coloured gems is far greater than the +50% loss on diamonds (because there are some standards with diamonds).
3. The technology, skill and costs of cutting a diamond are way higher than for colored gems.
4. Diamonds down to 0.15ct get graded at a big cost. Only a small proportion of gems come with a cert.
5. Treated diamonds are the exception. Natural gems are rare exceptions.
6. It costs 100's of millions to billions of dollars to prospect for and establish a diamond mine.

Don't get me wrong - I love gems of all sorts. I am not bashing gems. I am questioning the theory that diamonds are over priced and abundant.

 

[jordyonbass]

I always figured it was a lack of understanding on the difference between gem quality diamonds that are quite rare vs industrial grade diamond which is plentiful enough that we can make tools and other items from it on a commercial scale.

I'm in the Opal world and there is a similarity in the sense that there is absolutely tonnes of Opal scattered all over the surface here in Australia, but finding Opal with play of colour is not so easy. The major difference is that there's no use for the 'junk' Opal, unlike diamond.

 

[voce]

I don't think colored stones are rarer than diamonds. I think top quality untreated colored stones of some selected varieties are rarer than top quality (untreated) diamonds. If I want a certain quality/color of LI untreated ruby, there are far fewer goods available for sale and meet that standard than D IF diamonds, unless the diamond is of a rare origin or color.

With all due respect, @Garry H (Cut Nut), I don't think your points 5 and 6 really help make your point. 5 only confirms my opinion. 6, and 3 and 4 for that matter, doesn't have anything to do with the rarity of the natural mined gem.

As for 1, how many kilograms are mined each year, that by itself doesn't really tell the full story. How many tons of diamonds are already mined and stored in vaults before being presented to end buyers? Rubies in vaults above a certain quality, I suspect, are mainly in the vaults of private buyers and not in the vaults of ruby suppliers. I think of all natural gems, benitoite, Brazilian paraiba, cobalt spinel, and Mogok ruby are rarer than diamond, because production has trickled to nothing. I think all other colored GEM quality gems are more available, not rarer than diamonds.

The supply chain for diamond is so well established that it makes diamonds seem in abundance, even though that's not the case. Buying a diamond is way easier than buying a colored stone. There's also a psychological component there. What's easily available to buy doesn't seem that rare.

 

[chrono]

1. Don't know enough to comment on the CS mine output vs diamond
2. I think a 50% yield on CS is very rare. 30% yield is more common.
3. Don't know enough to comment on the technology, skill and cost.
4. I doubt many outside of PS care about getting diamonds smaller than 0.15 ct be graded at a reputable lab.
5. This is why untreated and well coloured CS are very expensive. The output from the mines might be higher than diamonds but good quality is very hard to come by.

I think it's not that diamonds are over-priced and abundant, but people tend to think of CS as cheap and abundant, when in actuality, high quality untreated CS are very rare and expensive.

 

[kenny]

I don't know about white, but lots of FCDs under 15 points are graded by GIA ... some quite $$$$$$.

 

[chrono]

I'm going to guess that Gary was talking about white, not coloured as he primarily deals with white diamonds.

 

[arkieb1]

Things like sapphires, emeralds and low quality rubies are not rare, things like cobalt spinels, jedi spinels, alexandrite, paraiba tourmaline, and many many others are rare and cost way more per carat than diamonds.....

 

[PrecisionGem]

Well the reality is, you can walk into most any jewelry store and view plenty of diamonds, or ask the jeweler to bring in 10 round diamonds of 1.5 to 2 cts for you to choose from. With in a few days they will have the stones for you to see. Ask them to bring in 10 tsavorite garnets in round cut, 2 cts. to view, and see what you find in a few days.

As far as yield in cutting goes, it's very rare to get 50% on a colored stone. I keep a database of all my stones cut, and track yield, my average is 32.7%.

 

[PieAreSquared]

You sound like a diamond dealer.

 

[shelovesinclusions]

...questioning the theory that diamonds are over priced and abundant.

But I see them as overpriced and redundant.

As a consumer who grew up in a home with a mother who loves them, colorless diamonds never got their hooks in me the same way colored stones have. I remember going from jeweler to jeweler with her looking for the perfect diamond upgrade to her imperfect engagement diamond. I really understand many people love diamonds. All round brilliant, ideal cut, IF, D color diamonds look precisely the same to me. So pricing seems variable based on local market and customer service vs a true rarity. Otherwise, why would there be so much service competition? Down to the chemical composition, aren't all perfectly cut, internally flawless, colorless, non-fluorescing diamonds essentially the same? They aren't so much of a rarity I couldn't find more than one in a day of shopping.

Additionally, it seems a good deal of marketing goes into getting people to buy into the concept of diamonds as a rarity in and of themselves in order to keep the prices high. This, in turn, makes diamond value feel very much like an illusion. There are no Mahenge spinel commercials out there on the radio- they are rare enough I would have to put in a chunk of time to find the ideal one, and even still may have to compromise. This same thing cannot be said about the standard box store diamond, which I can even pick up at my local outlet store.

I really appreciate rare cut diamonds, highly included diamonds & colored diamonds. But personally, the 1.5ct traditional diamond engagement ring is about as much my cup of tea as my "black" one is to a diamond fan. It just comes down to different people wanting very different things.

 

[Garry H (Cut Nut)]

As for 1, how many kilograms are mined each year, that by itself doesn't really tell the full story. How many tons of diamonds are already mined and stored in vaults before being presented to end buyers?
That has not been the case since 1997. It seems to take a while for people to catch up?
That last time De Beers did that was the Asian financial crisis and it led to the privitisation of De Beers with the Botswanian and Namibian Gov owning a sizeable proportion of De Beers. Journalists do not seem to want to write about that story???

It is hard to find real info because the gem world is so full of crooks and smugglers.
https://pubs.usgs.gov/of/2008/1013/ofr2008-1013.pdf that is the best I can find. Diamonds are around 3,000kg a year.

 

[Garry H (Cut Nut)]

Well the reality is, you can walk into most any jewelry store and view plenty of diamonds, or ask the jeweler to bring in 10 round diamonds of 1.5 to 2 cts for you to choose from. With in a few days they will have the stones for you to see. Ask them to bring in 10 tsavorite garnets in round cut, 2 cts. to view, and see what you find in a few days.

As far as yield in cutting goes, it's very rare to get 50% on a colored stone. I keep a database of all my stones cut, and track yield, my average is 32.7%.

Demand demand demand.
Diamonds make over 50% of the sales in an average jewellery store.
The cost of the support diamonds in each colored gem piece is often close to or more than the gem cost.
demand demand demand.

 

[Garry H (Cut Nut)]

Things like sapphires, emeralds and low quality rubies are not rare, things like cobalt spinels, jedi spinels, alexandrite, paraiba tourmaline, and many many others are rare and cost way more per carat than diamonds.....

If there was more demaned then they cost a lot more then there would be a lot more spent on prospecting for them.
So yes marketing has a place.
But durability is still king and so corundum is queen and all the rest are courtiers

 

[Garry H (Cut Nut)]

But I see them as overpriced and redundant.

As a consumer who grew up in a home with a mother who loves them, colorless diamonds never got their hooks in me the same way colored stones have. I remember going from jeweler to jeweler with her looking for the perfect diamond upgrade to her imperfect engagement diamond. I really understand many people love diamonds. All round brilliant, ideal cut, IF, D color diamonds look precisely the same to me. So pricing seems variable based on local market and customer service vs a true rarity. Otherwise, why would there be so much service competition? Down to the chemical composition, aren't all perfectly cut, internally flawless, colorless, non-fluorescing diamonds essentially the same? They aren't so much of a rarity I couldn't find more than one in a day of shopping.

Additionally, it seems a good deal of marketing goes into getting people to buy into the concept of diamonds as a rarity in and of themselves in order to keep the prices high. This, in turn, makes diamond value feel very much like an illusion. There are no Mahenge spinel commercials out there on the radio- they are rare enough I would have to put in a chunk of time to find the ideal one, and even still may have to compromise. This same thing cannot be said about the standard box store diamond, which I can even pick up at my local outlet store.

I really appreciate rare cut diamonds, highly included diamonds & colored diamonds. But personally, the 1.5ct traditional diamond engagement ring is about as much my cup of tea as my "black" one is to a diamond fan. It just comes down to different people wanting very different things.

Hey - I am the cut nut - so we are friends on the last part of your post. Re the first part - sounds like you might have been a Picketty Bernie fan?

 

[lilmosun]

I agree that price is driven by demand (relative to availability)...and broadly speaking, some varieties of colored stones might not as rare as white diamonds in terms of being mined

BUT I believe there is a lot more variation between what is being mined what the type of colored stone many in this particular forum seek..thus making them rarer than diamonds to many.

1) The same type of stone can have a wider range of varying characteristics that can greatly impact value. Obviously, diamonds have variations but I think they are more defined. For example, it's much easier to grade a diamond than it is a colored stone- where colorsaturation/tone all come together to create wide variations. Why the industry can't agree on color definitions, etc.

2) Adding to what @jordyonbass said. For many of those "common" colored stones, much of what is mined isn't gem quality - cut into cabachons or even worse, are enhanced for clarity and/or color to be sellable (why we caution on buying a stone just because it is guaranteed "natural" or "genuine").

3) It "seems" to me that there is more risks in faceting due to inclusions, color impact, color zoning, etc.

Last what is rare might also be subject to locale. I heard that some stones that are hard to find here are more readily available in overseas markets that are willing to pay more. But regardless, demand outweighs supply.

I say this not knowing much about diamonds (or colored stones for that matter, outside of what I like).

I don't often search for specific stones (mostly buy when I like what I see). However, when I do look for something specific I've often had to switch gears or wait a very long time to find a decently cut untreated (outside of low heat) stone in the right color/tone/saturation, size, shape. When I do, I feel like I hit the jackpot.

P.S. I like diamonds too but can't afford them. Most of my colored stones are small. For me, a small colored stone can make more of a statement than a small diamond..but that's just personal preference.

 

[Garry H (Cut Nut)]

I agree that price is driven by demand (relative to availability)...and broadly speaking, some varieties of colored stones might not as rare as white diamonds in terms of being mined

BUT I believe there is a lot more variation between what is being mined what the type of colored stone many in this particular forum seek..thus making them rarer than diamonds to many.

1) The same type of stone can have a wider range of varying characteristics that can greatly impact value. Obviously, diamonds have variations but I think they are more defined. For example, it's much easier to grade a diamond than it is a colored stone- where colorsaturation/tone all come together to create wide variations. Why the industry can't agree on color definitions, etc.

2) Adding to what @jordyonbass said. For many of those "common" colored stones, much of what is mined isn't gem quality - cut into cabachons or even worse, are enhanced for clarity and/or color to be sellable (why we caution on buying a stone just because it is guaranteed "natural" or "genuine").

3) It "seems" to me that there is more risks in faceting due to inclusions, color impact, color zoning, etc.

Last what is rare might also be subject to locale. I heard that some stones that are hard to find here are more readily available in overseas markets that are willing to pay more. But regardless, demand outweighs supply.

I say this not knowing much about diamonds (or colored stones for that matter, outside of what I like).

I don't often search for specific stones (mostly buy when I like what I see). However, when I do look for something specific I've often had to switch gears or wait a very long time to find a decently cut untreated (outside of low heat) stone in the right color/tone/saturation, size, shape. When I do, I feel like I hit the jackpot.

P.S. I like diamonds too but can't afford them. Most of my colored stones are small. For me, a small colored stone can make more of a statement than a small diamond..but that's just personal preference.

Nice considered approach

 

[shelovesinclusions]

Hey - I am the cut nut - so we are friends on the last part of your post. Re the first part - sounds like you might have been a Picketty Bernie fan?

I'm glad that's a point of accord. Who knows, maybe I would appreciate them more if I didn't live in suburbia where it seems the ultimate goal is for every woman to have a diamond identical, yet just ever-so-slightly larger, than the next.

But I need to ask- what's a picketty Bernie?

 

[Garry H (Cut Nut)]

I'm glad that's a point of accord. Who knows, maybe I would appreciate them more if I didn't live in suburbia where it seems the ultimate goal is for every woman to have a diamond identical, yet just ever-so-slightly larger, than the next.

But I need to ask- what's a picketty Bernie?

Thomas Piketty is a French economist whose work focuses on wealth and income inequality.
https://en.wikipedia.org/wiki/Capital_in_the_Twenty-First_Century

He was the prime influencer behind the policies of Bernie Sanders and Elizabeth Warren.

 

[shelovesinclusions]

Thomas Piketty is a French economist whose work focuses on wealth and income inequality.
https://en.wikipedia.org/wiki/Capital_in_the_Twenty-First_Century

He was the prime influencer behind the policies of Bernie Sanders and Elizabeth Warren.

Gotcha! Guess I should read up.

 

[Nosean]

Well the reality is, you can walk into most any jewelry store and view plenty of diamonds, or ask the jeweler to bring in 10 round diamonds of 1.5 to 2 cts for you to choose from. With in a few days they will have the stones for you to see. Ask them to bring in 10 tsavorite garnets in round cut, 2 cts. to view, and see what you find in a few days.

As far as yield in cutting goes, it's very rare to get 50% on a colored stone. I keep a database of all my stones cut, and track yield, my average is 32.7%.

Exactly!

And there are many gems which are normally not treated like garnets ( except some demantoid), spinel, peridot, tourmaline, almost all of the rare collectors gems.

 

[Seaglow]

It goes more than demand. Otherwise, luxury houses such as Van Cleef, Bvlgari, and Tiffany’s would have used sapphires and rubies as main product lines. But we see until now - the use malachites, topazes, aquamarines, and quartzes. Even if there are corundums, they remain it the collector’s edition or very commercial quality (overly dark or pale), or mismatched pairs of different colors. If I remember right, somewhere on PS there is a discussion that Bvlgari uses windowed aquamarines because of supply.

I go to Myanmar and I hardly see Burmese Royal blues. I go to Sri Lanka and the Cornflowers and Padparadschas are an effort to see if not nowhere in sight. In gem manufacturing capital of Bangkok, ask for a matching one carat suite (not even 2 carats) of blue sapphires of pleasant color, it will take some time to come in. Ask for a pair of vivid rubies, cornflower blue or pad sapphires over a carat for earrings, they are not immediately available.

If money is no concern, I can easily get a matched tennis bracelet of diamonds 1 carat each whether G-SI or D-VVS but it takes months or years to do that with rubies and sapphires. I will not even venture to no treatment, let’s include heated stones here (no glass-filling, no diffusion).

I don’t know about the statistics, but rubies and sapphires of quality are definitely rare with no cartel whatsoever.

 

[Bron357]

I think the fact is that there are many more diamonds “visible” to consumers than coloured gems.
I’ve been in a jewellery store overhearing a guy ask why diamonds are so expensive. “Because they are rare and precious” replied the sales lady to which the guy replied “well if they are so rare how come you have dozens just in this display cabinet? ”.
In the same Jewellers there will be a few sapphires, rubies and emerald pieces but the vast majority of stock will be diamond set. And that’s because they sell more diamonds but the fact the cabinets in any and every Jewellers you pass are full of diamonds makes them seem plentiful and therefore not “rare”.

 

[Lexililac]

The diamond business in the last century was mainly dominated by De Beers witch was (and still is very big) a monopolist and dictated the prices, quantity and quality of the diamonds witch enter the market over their rough diamond auction system. Beside spending year after year millions of dollars for marketing, "Diamonds are girls best friends" "Diamonds are forever". For me that looks more like a big fastfood chain, monopolistic cartel structures with a big marketing build up with the goal to sell as much as possible to everyone.

 

[Garry H (Cut Nut)]

It goes more than demand. Otherwise, luxury houses such as Van Cleef, Bvlgari, and Tiffany’s would have used sapphires and rubies as main product lines. But we see until now - the use malachites, topazes, aquamarines, and quartzes. Even if there are corundums, they remain it the collector’s edition or very commercial quality (overly dark or pale), or mismatched pairs of different colors. If I remember right, somewhere on PS there is a discussion that Bvlgari uses windowed aquamarines because of supply.

I go to Myanmar and I hardly see Burmese Royal blues. I go to Sri Lanka and the Cornflowers and Padparadschas are an effort to see if not nowhere in sight. In gem manufacturing capital of Bangkok, ask for a matching one carat suite (not even 2 carats) of blue sapphires of pleasant color, it will take some time to come in. Ask for a pair of vivid rubies, cornflower blue or pad sapphires over a carat for earrings, they are not immediately available.

If money is no concern, I can easily get a matched tennis bracelet of diamonds 1 carat each whether G-SI or D-VVS but it takes months or years to do that with rubies and sapphires. I will not even venture to no treatment, let’s include heated stones here (no glass-filling, no diffusion).

I don’t know about the statistics, but rubies and sapphires of quality are definitely rare with no cartel whatsoever.

Part of that problem is there is no centralised data base like RapNet, Idex, Polygon etc B2B platforms.
And that is largely because the gem industry has no standardisation.
That means there is no PriceScope for Gemstones
and so it goes

 

[Garry H (Cut Nut)]

I think the fact is that there are many more diamonds “visible” to consumers than coloured gems.
I’ve been in a jewellery store overhearing a guy ask why diamonds are so expensive. “Because they are rare and precious” replied the sales lady to which the guy replied “well if they are so rare how come you have dozens just in this display cabinet? ”.
In the same Jewellers there will be a few sapphires, rubies and emerald pieces but the vast majority of stock will be diamond set. And that’s because they sell more diamonds but the fact the cabinets in any and every Jewellers you pass are full of diamonds makes them seem plentiful and therefore not “rare”.

Take my store for example - we had a big colored gem jewellery push last year with Robert Procop. Our gem sales reached all time highs.
An amazing 13% of our diamond sales.
If you do not stock what clients buy you 1. get old stock issues. and 2. loose sales because you dont have what people want.
Ít is very rare for a store to sell anywhere near as much diamond as gems.
And if a store is selling more gems than diamonds - it is a business opportunity - add diamonds and double or triple the sales.

 

[Garry H (Cut Nut)]

The diamond business in the last century was mainly dominated by De Beers witch was (and still is very big) a monopolist and dictated the prices, quantity and quality of the diamonds witch enter the market over their rough diamond auction system. Beside spending year after year millions of dollars for marketing, "Diamonds are girls best friends" "Diamonds are forever". For me that looks more like a big fastfood chain, monopolistic cartel structures with a big marketing build up with the goal to sell as much as possible to everyone.

1. The EU broke up De Beers monopoly more than 15 years ago
2. Russia probably supplies more rough than De Beers
3. De Beers have not done generic diamond marketing for at least 15 years.
4. Generally a monopoly is greater than 50% market share. usually closer to 70%.
De Beers have not been above 40% for at least 15 years and are currently about 1.3rd

Competition And Monopoly: Single-Firm Conduct Under Section 2 Of The Sherman Act : Chapter 2

This is archived content from the U.S. Department of Justice website. The information here may be outdated and links may no longer function. Please contact [email protected] if you have any questions about the archive site.

www.justice.gov

 

[qubitasaurus]

1. The EU broke up De Beers monopoly more than 15 years ago
2. Russia probably supplies more rough than De Beers
3. De Beers have not done generic diamond marketing for at least 15 years.
4. Generally a monopoly is greater than 50% market share. usually closer to 70%.
De Beers have not been above 40% for at least 15 years and are currently about 1.3rd

Competition And Monopoly: Single-Firm Conduct Under Section 2 Of The Sherman Act : Chapter 2

This is archived content from the U.S. Department of Justice website. The information here may be outdated and links may no longer function. Please contact [email protected] if you have any questions about the archive site.

www.justice.gov

That is fascinating. I am not sure you are in disagreement with the rest of the opinions in this thread though.

It seems that more or less the consensus is coloured stones of a certain benchmark quality are indeed rare, but this is also true for daimonds. Some types of coloured stones are at least as common as white/colourless daimonds, some are rarer (also seen among daimonds though where some of the fancy coloured ones can be quite rare). Bad cutting is always a real shame, but results from a variety of factors ranging from surprises in the rough through to sloppiness. Always disappointing, but I think this thread is managing to articulate that many of us will forgive it if the colour is good enough (similar to how in a daimond someone may go down a colour grade for better cutting. It's always a trade off, you just pick your priorities slightly different in the two different cases. Many of us would say that with coloured stones colour is king. So if it doesn't have the colour I want then I unilaterally wont buy it. But as a trade I'll forgive some irregularities in the cut (Many of the stones are a bit too included to really see all the facets sharply anyway...) But people vary so I am sure many of them will prioritize cut irrespective of anything else. It's not a right or wrong answer kind of thing. And if you can find a way to considtently sell stones with neon colour that are untreated and an affordable price with precision cutting then I am sure you'll be swamped by the entire CS forum within hours.... I have no doubt those sales figures for CS vs daimonds will change overnight .)

 

[Garry H (Cut Nut)]

That is fascinating. I am not sure you are in disagreement with the rest of the opinions in this thread though.

It seems that more or less the consensus is coloured stones of a certain benchmark quality are indeed rare, but this is also true for daimonds. Some types of coloured stones are at least as common as white/colourless daimonds, some are rarer (also seen among daimonds though where some of the fancy coloured ones can be quite rare). Bad cutting is always a real shame, but results from a variety of factors ranging from surprises in the rough through to sloppiness. Always disappointing, but I think this thread is managing to articulate that many of us will forgive it if the colour is good enough (similar to how in a daimond someone may go down a colour grade for better cutting. It's always a trade off, you just pick your priorities slightly different in the two different cases. Many of us would say that with coloured stones colour is king. So if it doesn't have the colour I want then I unilaterally wont buy it. But as a trade I'll forgive some irregularities in the cut (Many of the stones are a bit too included to really see all the facets sharply anyway...) But people vary so I am sure many of them will prioritize cut irrespective of anything else. It's not a right or wrong answer kind of thing. And if you can find a way to considtently sell stones with neon colour that are untreated and an affordable price with precision cutting then I am sure you'll be swamped by the entire CS forum within hours.... I have no doubt those sales figures for CS vs daimonds will change overnight .)

Hahaha, yes, it is nice to discuss things with no demagogues. And thanks all for the discussion.
We do largely agree that really rare and beautiful gems are a wonder *and diamond itself is a gem).
I started a thread on Rocky Talky and arkieb1 suggested I move the topic to here.

GIA have been sending out videos - and the other evening I opened this one and was appalled at the cavalier attitude and unprofessional planning and faceting in this large emerald enterprise in Jaipur.
The diamond industry grew out of this slopiness 50 years ago in Surat India - now where 80-90% of the worlds diamonds are cut and polished. The Indian manufacturers adopted new technologies and wiped the floor with largely cottage industry manufacturers in other centres.
I naively expected that the colored gem industry had moved ahead too.

 

[MakingTheGrade]

For me, “rare” is a personal adjective and I think of it more as “how hard is it for me to acquire this” as opposed to how widely available it may be to the rest of the world or what tonnage of it exists lol.

I think of many of my colored gems as more rare than diamonds because the loss would be much more difficult to replace. Losing my padparadscha sapphire would be devastating because finding one that fit my specific tastes and budget took forever. Losing my bangle with ags0 diamonds would be aggravating but easily replaced.

Diamonds of large size, High or fancy color and high clarity are indeed rare and difficult to find, but most diamonds I see around me don’t fit that criteria. Until my gray diamond, any of the diamonds I owned were easily replaceable at similar price points as the original with the exception of the antique ones.

 

[qubitasaurus]

Hahaha, yes, it is nice to discuss things with no demagogues. And thanks all for the discussion.
We do largely agree that really rare and beautiful gems are a wonder *and diamond itself is a gem).
I started a thread on Rocky Talky and arkieb1 suggested I move the topic to here.

GIA have been sending out videos - and the other evening I opened this one and was appalled at the cavalier attitude and unprofessional planning and faceting in this large emerald enterprise in Jaipur.
The diamond industry grew out of this slopiness 50 years ago in Surat India - now where 80-90% of the worlds diamonds are cut and polished. The Indian manufacturers adopted new technologies and wiped the floor with largely cottage industry manufacturers in other centres.
I naively expected that the colored gem industry had moved ahead too.

Yes actually there is quite a lot of good information in this thread, and quite a few of the people here really know their stuff . So a lot of it is quite well informed.

I think perhaps your last comment strongly suggests that there was considerable market pressure for better cut daimonds -- such that better cut ones quickly out competed poorly cut ones. Also perhaps there was a large enough throughput for large structured organisations to emerge who had the capital to invest money into equipment to improve returns at some stage in the future.

If this was true, then one would conjecture (a) there just isn't the same pressure for coloured gems, perhaps consumers are more forgiving of wonky cuts (coloured gems are often not as much about sparkle or scintilation, many gem types are too included to sparkle irrespective or cutting or with a low refractive index, or come quite dark (perhaps too dark to get good light return to resolve the bottom facets) . Perhaps people find cut doesnt influence the appearance here quite as much. And accept inferior cuts.). If this is the case it's unlikely the cutting will improve.

Its also possible that there isnt as much material moving through, making larger scale operations less feasible. A smaller operation may have less capital to invest in improving their equipment and changing their approach. However It seems unlikely to me that you wont be able to find at least a few large scale businesses.

Maybe also there is a lot of irregularities in the rough and they generally find aiming for small but perfect really does mean 'very small but perfect'. Although again this wouldn't explain how something like sapphire which is often relatively inclusion free regularly turns up with a wonky cut.

Realistically maybe a collection of these factors are at play -- probably also other factors at play too. I would have guessed a lot of it has to do with customers being more lenient such that the badly cut gems were more marketable.