When at university in the late 60's and early 70's, as a physics major and then as a post graduate research student , we frequently had to use "obsolete" equipment due to funding issues and in some instances due to the fact that the exact equipment we needed simply didn't exist so we sometimes built new equipment or modified older so called obsolete equipment to achieve our ends. Part of the training was to calibrate such equipment against known standards in order to to achieve and maximise the resultant accuracy of such equipment.
I think that the same philosophy also applies to our cameras and lenses in achieving desireable photographic outcomes. There are many such examples of people on this site who have used "obsolete" cameras and lenses to this end:
* modification of non-Ai lenses and non-Nikon lenses, chipping of lenses, and adding new lens mounts via adapters or machining new mounts, e.g. the work of Erik, Bjørn /nfoto, and Dr Klaus Schmitt readily come to mind, and there are many many other examples here on this site
* converting DSLRs to see further into the UV, IR, or to have broadband spectral responses, e.g. see Thor Lidason's splendid IR images posted here recently and likewise those of Bob Friedman and many others here on this site
* modifying tripods, bellows, stands, electronics, and flashguns (often to do UV work)
* creation of panoramic heads, e.g. Seapy, or fittings for special purposes, e.g. Erik's fascinating special fittings made to allow a 6mm(?) fisheye lens to be more easily handled in the field.
* lastly the creation of colour profiles and the use of up to date RAW file processing can often drag more out of a raw file - for both obselete and current models of camera I must admit.
Photographers and people working in any of the technical spaces are pretty good at adapting or repurposing their tools to new uses or to extend their useful lifes. Nothing is entirely obsolete if placed in the right hands and with some imagination. Go back a 100 years and the obsolete gear of today still looks pretty good to me.