Copyright does not meaningfully harm creativity. Sure, you can't publish your Harry Potter fanfiction. But you can borrow all the themes you want from it. Magic schools, mysterious back-stories, dark lords and flying brooms can't be copyrighted.
Moreover, Disney cannot prevent you from using Pinocchio, Little Mermaid and the rest of the public domain stuff they have used.
Effectively unlimited copyright leaves a hole in the availability of older books, making it impossible for there to be any growth on top of them.
There is an enormous amount of Harry Potter fanfiction. You're restricted from selling it though. But, as an author of twilight fanfiction proved, when you're ready to sell you can just find and replace some names and be good to go.
As a result, we can't view those shows in their original, and as I described, iconic, format -- or sometimes, at all -- except haphazardly on syndication or through piracy.
I mean, shows that e.g. everybody would sit down at home and watch on Monday evening.
Tell me that doesn't have a cultural impact. As just one example.
Copyright is in serious need of reform. You're granted a limited monopoly, not total, perpetual control -- nor the right to remove what were public, cultural objects from public discourse.
Something similar is at risk with regard to the news and other reporting. Watch copy vanish from the Web. At a minimum, there need to be modern libraries of such content where access is guaranteed. It represents the continuity of our history.