People are still buying them no doubt. I've seen them at the flea markets since I was a kid. And although there's no longer hundreds of boxes like there use to be there's still generally a couple tables dedicated to the bootleggers. It's pretty funny that fleamarkets allow it, happens right in the open and noone says shit.
As far as selling them online your best bet is to build a list.
I was doing this long ago before I even knew how to build a website.
I was on seduction forums back then and got a message from a reputable member who told me he had every seduction seminar, underground video, etc that exists and if I'd like to see the list. He didn't even mention anything about money so I didn't take to it as spamming.
But when I saw the MENU, and some of the shit he had I immediately ordered over $100 worth of DVDs.
Then a month later made another large order.
One day he accidentally sent an updated list with the send field loaded with emails. Had to be like 50-70 emails (I never counted). Then he apologized. I was so stupid I didn't even realize what he did till later that day. So I ordered another $50 or so + 100 blank dvds on ebay. Then emailed his little list and got just a few people email back excited about the discounts. Then a few more asking "who are you?" and I gave my forum handle. I started getting money, burning the DVDs, mailed them out. Built my stock. Updated people once a week. Messaged others on forums. That was a nice little side hustle while it lasted.
The 1 thing that surprised me was when I found out this guy was just finding these from torrent sites and places like rapidshare. When I first started buying them I thought he was getting them legit from ebay, peoples websites then copying them. Cause I ALREADY KNEW and ALREADY TORRENTED what I knew about. The lesson I learned was I SUCKED at sourcing titles or even knowing that certain tapes existed. Like his underground tapes were illegal. It was a lair of guys going out taping women, not censoring their faces, not censoring anything or telling them they were being taped (inside private clubs and bars). Then they'd show everything. Guys getting blown out. Guys getting numbers. Some of the shit was softcore porn. These tapes were unusual cause most seduction tapes didn't show this type of shit. And that ultimately motivated me to start my own "lair" and start doing that shit.
At any rate, this was like 8 years ago. These days as much as things have changed people still suck at finding certain things online. You just gotta find what that is, where the buyers are, how you're gonna pitch it and build your list. I'm sure in poor urban ghettos people still walk around trying to bootleg shit. But obviously online you can buffer yourself a bit.
-BB