Young people don't have the same kind of disposable income as the pre-1980s generation did.
The $5 an hour I earned in 1972 is worth a lot more than what kids are making for the same job today.
Gun values were a lot lower relative to earnings as well. 10 hours labor would get me a good used handgun or rifle and less than half that for military surplus.
My latest revolver cost $300. How many hours would a typical 18 year old kid have to work to earn that, if they can get a job?