As far as stifling innovation, one only needs to look at the recording companies. The resistance to new technologies, easier ways of accessing "content" - that's definitely restricted by the application of copyright laws. One recent example is Zediva. Copyright then ends up concentrating on a few companies that were able to make deals, rather than ones that are continually innovating in technology. Look at how long it took to get "legal" access to The Beatles music as MP3s.
I don't think you can see copyright as not stifling innovation in those areas.
But, I suppose, we could argue that it's just the horrible overapplication of copyright laws that are stifling innovation. A weaker copyright system would probably work out just fine.