A few random thoughts:
Cars are a durable good, not an investment. Past price appreciation is not an indicator of future value and auction prices do not always represent real transactions.
Many "collector" cars are caught in what I call the mileage trap. Much of their value is tied to their being low mileage originals and if you actually drive the vehicle you're eroding its value. What is the point in having something neat that you can't enjoy? Also, disuse is not good for a car or any other complex mechanical assembly. Anyone who has returned a car to service after a few years of sitting knows this.
Most of the American and volume produced European and Japanese cars went through a period where they were just cheap used beaters and it takes a whole lot of expensive work to bring these cars back to some semblance of nice. You see lots of bad rust repair at every car show and most of these cars were also terrifically rust prone at least into the 'seventies. Also, most of the deceased old man owned pristine originals are now in the hands of others, so the limited availability of these cars has pretty well dried up.
Finally, cars are fun whatever generation you belong to. Having a nice old ride to enjoy during the summer is a pleasant hobby as long as you have a place to store and maintain the car. The cars as investments market will crash at some point and we may already be seeing this. That will return a bunch of interesting cars old and newer to the hobby market where people will then be able to own these cars at more reasonable prices. At least I hope to see that.