Not gonna happen anytime soon. Try buying a book on the Amazon app, you can't download an ebook. You buy the ebook through the website and download it to your Kindle account and then it'll show up on your iOS app. If iTunes don't make money, nobody makes money.....in the Apple universe. It's going to be interesting to see how they keep the fence up after they introduce their "file manager" on iOS 11. If I was a betting man I'd say MP3 files and epub files will remain verboten. Also, nobody has said anything if iOS devices will have mass storage capability.