Cost is one of the biggest issues. The young people I know spend all there money fixing up there house and things like that. They have told me it's cheaper to stay at home and grill out in there yard then what it is to go to the park and do the same thing. Plus, well, there is no easy way to say this, but because they are young and have older vehicles they are more likely to be pulled over by the police, talked to, and searched. Sure then they get set free because they are doing nothing wrong but, it's just a hassle. And, maybe this is something wrong, a burned out license plate light, or something. There was a time when you would be told to get it fixed. These days a ticket is more likely to be issued, so that is another cost.
It's a lot cheaper and less hassle to stay at home.