I think a lot of it is $$$. Yeah there are already so many morphs and so many combinations that haven't even been created with existing morphs. But whoever finds the "next big thing" can make a lot of money. I mean some new morphs go for over $50k; imagine if you discovered a new morph and got to name it and produce it and combine it with other genes etc.
I agree with you that there's so much that can be done with what we have, but I also see reasons for wanting to import. Now that being said, I think you raise some good points about what about all the "normals" that don't pan into anything. I'm sure there are some irresponsible people who probably just get rid of the animal ASAP without much regard for her health and what not. But so long as there is $$ to me made in the numbers, the search is always going to be on for the next big thing.