I think this is a good point, and it is one of the reasons I am not very concerned for the long term storage of my negatives and/or digital files that have never been printed. Since I only print by contact I have a print of some type of all my best work that should have good permanence, as well as a negative. Even images made originally with digital capture must have have a negative, same as the images originally caught on film and then scanned.
Along the way I have produced thousands of other negatives with various format film cameras, and recently a fair amount of files from digital capture, which has never been printed for one reason or another (mostly because I made a conscious artistic decision to not print it). My thinking is that if I have never made a print from a negative or digital file the material is essentially not relevant to my work as a photographer. In fact, assuming that I am given the time, before I die my intention is to do my wife and family a favor and destroy all of my negatives and digital files that have never been printed.