"Unstructured time with other kids" is also the source of many many problems (as you acknowledge). Especially if the only destination is a gas station.
Kids need parks, sports fields, cinemas, hobby stores, places to get food, etc, and they need them within walking distance. Being virtually dependent on cars to get anywhere is very crippling for kids.
Being dependent on adults to drive cars is the crippling component.
If there were free taxi services (or other transit), kids would be fine.
And honestly, most of the evil comes from overly-empowering parents. "I don't think you should go there / do that / hang out with those friends" is toxic.
Healthier, as kids mature, for them to be able to do things that parents disapprove of... but can't stop. While still allowing prevention of serious choices.
Making kids dependent on parents' cars increases parents' power from "I can speak out about things I disagree with" to "My agreement is required for anything to happen."
And that's really not healthy, for the kid or the parent.
Do you have any evidence of that? Asian American parents generally strictly control their kids’ choices, and they have much better outcomes than white American kids.
I think it would be great if kids could take themselves to gymnastics practice on public transit. But giving them the choice between that and smoking pot with friends? I think the choice hurts rather than helps.
What do you mean in the second paragraph about gymnastics practice? It's implying kids cannot take public transit, but why? That was fairly common, even recently, and I'm trying to understand if something has changed in some regions.
My roaming range on my bike was about 5 miles in any direction. All of those places cost money. I'm not sure what kind of childhood you had, but I didn't have a job at 14, and those are places I rarely went. What you seem to be advocating for is a credit card more than a ride.
Kids need parks, sports fields, cinemas, hobby stores, places to get food, etc, and they need them within walking distance. Being virtually dependent on cars to get anywhere is very crippling for kids.