I guess there will always be a place for new media and new books, but I think the problem is not that no more are ever needed. It's more about how to choose.
I'd like a store like steam, but where they limit their selection to maybe a selection of 100 highly curated games. And change that selection from time to time.
A bit like when you go to the library, they have already done the effort of choosing what books will be on display from the vast collection of books that exist in the world.