https://voxday.net/2022/09/29/its-not-your-imagination-4/

You could also view this as a failure of community, wherein past decades had more functional public life and kids ran free and participated in more activities that did not require parents to mind them for those additional hours.

Personally, I don't see this graph as necessarily improved from past to present generation. It can equally reflect an added burden on parents due to paranoia or lack of perceived safe community "third places" and childhood freedom to roam around town to friends houses and activities.

Tom Sawyer didn't need his mother to watch him paint that fence unsupervised, but today's mother wouldn't dare let him out of sight.

The Beaver could walk down to the pond and fish or play while his parents June and Ward did their own activities around the home, but today there either isn't a pond or parents would be fearful of an unlikely drowning, kidnapping, etc.