Yeah, that could be a concern. Although it would be trivial to mitigate that risk - assume that they'll only last 1 year and replace them annually. That would be a bit of a pain for 10GB, although migrating to DVDRAM would reduce that too.
Actually, that's how I backup my photos - I take a copy on CDROM to my parents whenever I visit. Admittedly I only have about 1G of photos so it is fairly easy to do. But at least I know that short of all-out nuclear destruction, or a huge asteroid strike that wipes out mankind, my photos are safe. Off-continent storage rocks.
(I'm not too concerned about whether they survive those events!)