"The challenge is to find, say, the $10K speaker that sounds like those $100K "high-end" ones",
Well, there are some giant killers out there Ack, largely the small manufacturers selling direct. I spoke to just such a small manufacturer a couple of years ago, who estimated the material, labour and delivery costs of a $80000 loudspeaker, was probably $20000, including a modest profit. The rest is marketing, dealer and distributor margins, which can easily add 50% to the cost+ a large margin to the manufacturer.
Who are they? Well ones I have heard myself, Devore, Silverline and the ones I bought and am very happy with, Daedalus. Others I have'nt heard, but who you hear good things about, Vapour, Tyler, Odyssey. Vapour and Odyssey get uniformly good feedback at the shows, from reviewers, as does Daedalus of course.