Not a darn thing wrong with that though. That's a market. A niche. He used his talent to make a fortune while he was alive. Very lucky and very smart. He choose the commercial route and I can't see anything cynical about that. Now if he is cheating his franchises that's different but that' his business side..not the art itself.
My only quibble with Kincaid is that I seriously doubt all of his "original" work is original. I wouldn't buy his work, but if someone else wants to, that's their business.