I think the kindle books are still available if you login at the right url. They were for a bit, long enough for me to download them. It's difficult though. You're just fucked. I have like four kindles though and they work fine without an Amazon account. Never even need to turn the wifi on. Getting books on there with a USB cable is slightly annoying but not really. I don't know about any other product. I recommend avoiding all drm content for this reason. Luckily kindle books can have their drm easily removed. Not that I'd ever do that cause it's illegal. Lol.
I've got tons of music - mp3 songs and albums, hundreds of both purchased Kindle books and uploaded personal ones, Audible audio books, years worth of pictures that was part of some hardware deal, etc?
Its even worse than the problem of Google just shutting down your account since most of these victims weren't paying for anything.