It might sound silly, but people said 1960s Mustangs would be worthless down the road due to their having been millions of them manufactured.
Now, I get that those cars were more quality-made than the plasticy Cavalier, but my question stands: Do you think, 20, 30, 40+ years from now, if you have a stick-shift Cavalier (or even an automatic) that it could actually go UP in value?
There is an old saying; If it was popular in its day,,, it will be again. Years ago, few ever thought the GTO, Chevelle, or even Grand Prix would ever be worth much. Try to buy a decent one now.
There is a good chance some Z24's may go up someday. The supply is very low, after cash for clunkers destroyed so many. I'm keeping all of my 2nd gens, but not because I think they may be worth big money, just because they are the last of the cars that have features I want, without all the crap I don't want. I tell people, 1994 is my cut off date. I don't want anything newer. So, even if they went through the roof some day, I'd probably still keep them.
I think it is based on nostalgia. If people have disposable income and a yearning for a car from their youth then they will hold some value. However, this will need to balanced by the cost of restoration. Look at bring a trailer. People buy (and spend more than I ever thought they would) on all sorts of weird cars.