I think we should be borrowing a page from the torrent tracker community and establishing invitation/interview only markets for buyers. Reddit has it's own private torrent tracker that has a max user count of ~6k and it works very well.
That is not to say LE wouldn't be able to infiltrate these markets but it would reduce LE interest if there are bigger/easier fish to fry. It would also serve as a way of filtering out users who are technically inept or who are simply unwilling to go the extra mile.
Maybe these already exist is some form and i'm just not in the inner circle. If that's the case then i'd love a pm :)
Running a market isn't as easy as downloading software. You need front-end and back-end devs, servers, hosting, sysadmin on call 24/7, moderators, admins, and other staff. All of this requires a decent amount of start up costs which few people have. Then on top of that you have the added stress of keeping the market secure and keeping OPSEC as tight as a baby's asshole.