GrumpyPa ... and the stupid twiddly plastic bits and short-run castings that infest modern cars ... 3d printing will help, but there's so much of it that it's hard to see setup costs being viable for handfuls of cars that just happened to use those bits for a six-month slot in the production run. Most old cars survived because somewhere down the line someone had the motivation to keep them running while they were just 'old' rather than 'classic' ..
I see that as a crucial missing link.
K