Eh, maybe. Most people don't understand how to preserve anything, digital or analogue. If you can say "but my toned FB prints will live for a millennium!", you're in the vanishingly small minority of people who know what they're doing.
Digital has likewise got a few people who know what they're doing. People who use RAID and offsite backups and actually make use of the fact that you can make an infinite number of lossless generations of copies - their photos will last as well as any FB print, will never be stolen or lost in a fire or flood. As the web gets more prominent in people's lives, I suspect that there's a lot of history that will live on in flickr and similar sites and while having that stuff held by a private corporation is a bad, bad idea, there are more open, distributed and fail-safe solutions starting to take shape, at least in universities.
Can you guess my PhD had something to do with distributed filesystems?
My prediction is that within a decade or so, what people refer to as "cloud" or "grid" computing will start to become more of a reality than the buzzword that it is now and reliable long-term archival of data will become available to the general public. Photos will probably be one of the first things to go on there.
At the moment though, Joe-six-pack with the one copy of his photos on one hard drive or CD-ROM? They'll be lost irretrievably soon, just like C-41 negs and Ektacolor prints.