Originally Posted by nogle
With a physical book, if you forget how to read or burn your book, you also lose the book. With an eBook, as long as you maintain software capable of reading the file, you can read it (assuming again that you maintian the ability to read). As far as I am aware, the onus is on the user to maintain the ability (software) to access the file.
There have been cases where companies have dropped their support for their DRM schemes -- check out Microsoft's PlaysForSure for example. Once they turned off the servers, you couldn't add a new computer to play the content nor could you re-authorize an old computer if you rebuilt or upgraded the operating system.