Forget about AI. Instead it is almost the entire art industry, wholesale!
The semi-professional online art commissioning market is almost entirely copyright infringing fan art works, being sold without permission of IP owner.
Yes, fan art is infringing. Especially when it is sold. And if you go to a convention center, to the artists section, you will see that over half of the booths are straight up selling other people's IP without permission.
This is the case for conventions, online art commissions, etsy/handmade items, all of it.
Its all illegal, all infringing, and the only reason why anyone cares now is because someone else can do the same thing that others have been doing for decades, but quicker and cheaper.