Big rejection numbers in publishing are not important. Big numbers in general are not important. No, the number to worry about is one. One. That's how many sentences you have to impress an agent or editor.
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.