I really do not think there is as much inbreeding going on as you think. Sure, maybe a generation or two, especially when proving a morph, but after that everything is being bred out to other morphs to get combos. Someone mentioned spider, came from one wild caught animal, like many other morphs. Yet how much do you think it was inbred, what happens when you breed a spider to a normal, what do you get, more spiders, not much reason to breed them together. Clown, or any recessive, once it was proved, people wanted to mix it with other morphs, so what happens, you outbreed to something else, then maybe back to the het mother, or two siblings together to try to get a visual, but this likely happens only one or two generations till you start getting visuals and then 100 percent hets then outbreeding you know what you get.