One problem is that in a good economy there are people with 10k that want to buy a classic. They go to CL , FB or ebay and start looking at cars in their price range.
Lots of 4-5-6k car with a 10k asking price.
The uninformed cough up their 10k for a car worth half that.
They put another 5k into it and think they now have a 20k car.
As the price goes up, there are fewer buyers. Those fewer buyers for the most part have a much better grasp of value and recognize a quality car vs a lipstick on a pig car.
My 67 is a lipstick on a pig car, but I traded a lipstick on a pig car for it. The PO used elcheapo parts, but the body is rock solid without the usual rust issues. When I sell, somebody is going to get a great blank canvas to start with.
1965 Mustang Coupe 289/C4
1967 Mustang Coupe 200/C4
2017 Mustang EB Premium