When I bought mine 11 years ago I paid $1675 for a car with a few rusty spots, a dented door, fender, and no interior but it did have a freshly rebuilt motor that has been going strong since then. My criteria was to find a car that was SMOG exempt in CA, was sporty, had support from the racing community, was fun to work on, is still practical for caring stuff around, and can be driven everyday (which I have done with mine for the entire 11 years.)
If we're being honest, there are not too many cars left that fit this criteria. These cars will go up. Having said that, I've noticed young people either shoot a rocket out of their pants when they see it or are completely oblivious so I have to think at some point there won't be a very broad interest in classic cars and kids just don't care much anymore.