And a big part of that is ignorance--folks don't know that they are buying fakes--while another part is cost, convenience, and communication and access. To get a Beto sculpt from the source is frankly not easy. Beto sometimes ignores e-mails, sometimes takes a long time to respond, sometimes makes sculpts available, sometimes doesn't, then sometimes takes a very long time to deliver when he does. Trevor Grove had similar issues with his sculpts, which are now available, but at a premium from a seller that isn't always responsive to customer inquiries. And collector X who wants a nice Breaking Bad or Michael Myers custom could either wade through all that, ending up paying $150 or $200, and waiting many months to get their sculpt, or paying $50 for a rough recast on eBay and get it in a week. Many won't be stopped from doing this by a concern over treating the artist fairly.
I'm not criticizing anyone here. Folks who create these things can do what they like in terms of selling them or not selling them. But if you think the real problem is the folks that are buying these sculpts, then I say the solution is trying to find out easier, more affordable, and more predictable methods for folks to get legit sculpts. Otherwise, the Qs of the world will continue to crop up and flourish, and all the complaints in the world won't stop it. Rainman started making his sculpts available, essentially on demand, once or twice a year from the source for a decent cost, and I think that has worked pretty well for him to cut down on those who would try to capitalize on his work. Sure, Q is still selling recast Rainman sculpts, but I think more and more collectors are now going to Rainman because they are made available, and customers know the quality is better, the price is equivalent, and the artist is getting rewarded as he should for what he created.