Re: But what about Kindle books?
And therein lies the rub. Not just with this, but with the Kindle, anything with 'i' at the start of its name, and several other offerings.
I really do think we've gone backwards - back in the 70's there were the Unix wars and other such events which basically revolved around big companies trying to lock-in their customers. Everyone sighed with relief when this all came to an end with the open architecture that was the PC. Even when MS got its claws on it, it's Mickey Mouse OS's were still pretty open and you could pretty much do what you liked.
Since Apple started to rise from the ashes, we have (and still are) inexorably falling back into a culture of lock-in. Except it's arguably even worse now because what is being locked-in is stuff that has previously been open and freely available (and no, I don't mean pirate-able), like music, and books and other media. I'm guessing it will go on for a few years (maybe a decade or so) before someone comes up with another "PC" and suddenly everyone will be sighing with relief at the "new" open architecture that we can pretty much do anything we like with. Until then, it looks like walled gardens (gilded prisons) , lock-in and general control over what we do and what we don't do with stuff we've bought will continue for some time.