That's very true, especially of Jnats. The Japanese will pay far more than most any of us because the best stones are the tools of journeymen craftsmen and as such command a price like a good bandsaw or table saw which we have less ideoligical problems paying for.
Browsing a Japanese shop inventory I saw a nice large (as in 8"x8"x2") suita at $6000, and a good Hatahosi-branded Hatanaka bench stone, $4000 and up. These stones would be practically impossible to sell in the West, so we tend to see stones that are cheaper because of lines, irregularities, imperfections, missing corners, etc. This is not necessarily a bad thing as that $4000 benchstone quality may be only $250 if it is an irregular koppa in the barber hone size.
Cheers, Steve