As men wearing suits analyze the death of Borders, it's become clear that none of them grew up kissing books. They blame book readers, digital books, Amazon, and the recession for the demise of the chain when they should be blaming the executives.
So, again, how permanent are digital media? Just about as permanent as we want their contents to be. Whole dynasties may be lost, as Shelley's "Ozymandius" illustrates, but @Dadboner is an example of a literary artifact worth preserving.
In the end, the act of writing a book will not change. Yet as the publishing world changes, as do the ways in which readers digest books, many of the most meaningful moments in an author's career will be lost or different in a way to make them unrecognizable.
As scientists improve their ability to manipulate the genome, will a market might emerge for people who want to imprint quotes into their own DNA, or even their children's, as a sort of genetic tattoo?
Many great writers have also been great drinkers and their advice around this habit will either want to make you keep going or will stop you forever. But do try not to spit out your scotch laughing at the wit.