There is a correlation with urban sprawl and the autonomy of children[1].
Depending on where you live, it's harder young people to get around compared to 40 years ago. Like this HN user's experience in this same thread[2].
By making society car centric we have made it difficult for children to exercise independence even if their parents allowed them to.
In a non metro area your options as a teen to go somewhere are to beg your parents to drive you somewhere or to walk for hours to a bus stop. These barriers and the rise in pedestrian fatalities do not incentivize autonomy.
[1] https://youtu.be/oHlpmxLTxpw Why we won't raise our kids in suburbia