The problem is, digital is even more dependent on the presence of an "industrial infrastructure" than film. Sure, the camera itself may still work after 15 or 25 years...but that's assuming you can still get batteries (D1's use complete obsolete NiMH units) and memory cards (C41 film will almost certainly be available long after CF cards are all but unobtainable) for it, and that the computers in 15 or 25 years will still run the software needed to process the images, etc. Not to mention the inherent fragility associated with the complexity of these sorts of cameras. Older Nikons are susceptible to developing a fault where they are simply not able to read the memory cards. If you don't mind doing some semi-major surgery, that can be corrected, but how long will spares be available?
There are already all manner of early digital cameras that are effectively technological orphans.