The market has weakened substantially for pre-war cars. Even for cars up through the 1960's. There is a declining pool of buyers as time passes. Young folks just are not connected to these cars emotionally or otherwise. No young person in their 20's has any personal connection to a 1960's era muscle car, yet a pre-war car.
See post #18 in this thread.
https://www.fordbarn.com/forum/showthread.php?t=357279