The way I figure is that anybody with eyeballs and half a brain can look at a negative and see the picture. I'm sure that the technology will exist, SOME kind of technology, way off in the future to convert the negative image into a positive. The point is, you can actually SEE the picture. Will somebody far off in the future know that if you rotate a black plastic disc at the right speed it should be possible to "read" the vibrations it would make on a needle and hear music? And those little silvery discs? How the hell can they be read? Guess wrong? Is this one pictures, music, or simply data storage? We're cursed with analog brains, and they seem to function in an intuitive way when dealing with analog subject matter. On wedding forums folks are always seeking salvation after inadvertantly deleting their files or any of half a dozen other problems because one "film" card looks like the next whether full of images or not. Calling them "film" cards doesn't make them any more archival.
The silver prints hold up pretty good also. I've got a pair of 11X14 prints on my wall of old square rigger whaling ships, signed and dated 1906 and 1918. My son now has the family archives, including photos of my great grandparents from the 1890's. Sure, he could save storage space and scan them all. Fifty years down the road those enigmatic little silver discs would all be off to the landfill, a family's history gone forever. Yup, I'm a fossil, unwilling to jump on the digital bandwagon.