While I know, at 69, I am no ones radar for car buying habits, I remain opinionated
I DD a 30 year-old SUV that drives like a sled, is noisy and gets two dinosaurs to the mile around town...but I love it and it makes me smile: Mainly because I bought it nearly eight years ago for $10k and have maybe another $8k in it.
Like my DD, other than lust and cool, there are few performance reasons to own an air-cooled Porsche...perhaps to go slow fast and work on those numbers...I don't know.
The only air-cooled Porsche I would consider is a 964...I had a 1994 964 Targa which I would still own if I had not been run off the road. Even then, at the current price point I'd probably not want to drive/own one of my favorite heroes again.
I don't think the market for older Porsche's will, as a friend of mine says, 'Acapulco' (think Wide World of Sports cliff diving...I know) because of frankly low production numbers, they can keep up with modern traffic and they are and will remain iconic.
In my parts of the world, Maryland and SC, there is a strong market for older, small trucks and SUVs...I see at least 2 80's/90's Ford Rangers a day being driven by young men that are absolutely perfect, annoyingly so.