Well, you don't need to be a genius to be creative. Also, who is to say that some entrepreneurs aren't geniuses? Just because they apply their intelligence to business instead of writing novels or proving theorems, doesn't mean they can't be smart.
I think human beings, and animals for that matter, are naturally entrepreneurial. In the wild, those that aren't would die a quick death. Its only when there was work that could be done by non-entrepreneurs that they began to thrive. Well, subsist anyway.
