I guess I see location as being akin to a 'brand' - Crummy Burmese rubies will appeal to customers who've never heard of Madagascar the same way Tiffany can sell silver 'key' pendants for a hundred times their cost of manufacture. As you say, savvy consumers will come to realize what they want (colour, clarity and look in a natural stone? Why pay Burmese prices?) the same way gearhead car owners will praise Camaros or Subarus over Porsches and BMWs. Some purchasers are in it for performance, others for a logo. Ultimately, if the look is all you care about then there are definitely cheaper ways to achieve it than buying natural gemstones, regardless of their source, so to some extent we're all in it for rarity.