Car-centric society has made it damn near impossible to walk.

Those six blocks you used to walk have all had their lanes widened into stroads, one converted into a thoroughfare, and no attention was given to pedestrian infrastructure so crosswalks, sidewalks or bike paths are almost non-existent unless you're within 2 blocks of the school.

We have literally built most of our cities, or redesigned older cities that used to be pedestrian friendly and walkable, into a wasteland of asphalt and concrete designed exclusively for personal vehicles.

A vicious cycle happened. 24 hour news reports every child abduction basically in the country, making parents feel that they're more common than they are. Kids freedom starts getting restricted. There's less kids outside, so parents are less comfortable letting their own kids out, and kids have less incentive to go out. At the same time, the number of indoor entertainment options explodes. As they stop being seen outside, the world adjusts to life without them.... Less crosswalks, less bikeable areas, less parks. With so few kids being outside the house, the parents who still encourage their kids to play outside or go do things become the minority and law enforcement fucks with them accordingly, as in this story, making parents even more reluctant to let their kids out of their sight.

There's some resistance to this. Free Range Kids comes to mind. People see the problem and want to do something. But as you can see even in this thread, people have so accepted "kids should stay inside supervised at all times" as the norm that it's an uphill battle.