The permissive license certainly has got a few corporate players in the mix and that's a good thing. I don't know that it has resulted in a lot of innovation or major transformation/codegen work that wouldn't have happened anyway. Certainly various organizations are holding things back and keeping then proprietary. It's really had to guess the "what ifs."
Certainly Apple would not have worked on a GPL project and this would not have hired Chris Lattner. So while it's interesting to speculate, it's impossible to know where Chris would have landed or what would have happened in the alternate universe.