That's true. thinkcomp's argument probably should be that the reason the largest exchange is in Japan is because of U.S. regulatory regime. There have been legitimate contenders (TradeHill) who had to shut down because of regulatory issues, or banking issues related to regulatory issues.

That's not even counting the serious entrepreneurs who passed on the opportunity to establish a competent exchange because they knew it wasn't possible to establish one legally without tens of millions of dollars.