silver

I am getting more and more radical in my thinking about the evils of copyright, especially when said rights are controlled by anyone other than the actual creator(s) of a particular work.

But I guess that's an argument for another day and (maybe) for another space.

I think Scalzi (I really need to check out his fiction one of these days!) touched on the answer to your main question, in his Point 2. Namely, I suspect Amazon sees the real money here coming from the original creations to which they will own all rights. Every once in a while, they figure, will appear another 50 Shades of Grey, another Spider-Man, another Star Wars, created by a wide-eyed and innocent fan who is expanding on something they love — and who will never see more than a coupl'a hundred bucks from the people who bought her (or his) fanfic through Amazon, while the Major Motion Picture makes zillions for the corporate overlords.