I have a kindle, and I very much like the convenience of being able to manage my library by easily moving books on and off of the kindle wherever I am. However, any time I buy a book from Amazon I first check if a DRM-free alternative is available elsewhere. I don't do this because of principled opposition to DRM (I am opposed to DRM on principle, but it's not why I do this); I do it because I want my books to be as portable as possible, not locked in to any one merchant, platform, or device. Unfortunately, in most cases the only option is a file with some other form of DRM that won't work on my kindle. If the big publishers stopped using DRM, I would stop buying ebooks from Amazon and buy all of them directly from the publishers.

If such were to happen, I'm sure that other people would offer cloud services that would allow you to upload your eBooks from wherever you buy them and then access them from your device over your choice of wireless carrier. If they lost enough market share, I'm sure that even Amazon would start offering such a service.