https://www.washingtonpost.com/sports/2019/06/04/fewer-kids-...
It may be social, in that letting kids roam on their own is not as acceptable and could get you in trouble with courts. Also, "cars" are more dangerous these days, ans they shift into more trucks and SUVs with massive blind spots and distracted drivers, and there have been many efforts to eliminate penalties for speeding, and the difference between 20mph and 30mph is literally a ton of death.
The number 1 thing I would love for my child is to live in a place where I was not in constant fear of cars when on the sidewalk or street. It wasn't like that when I was a kid in the suburbs in the 80s. And I will likely have to leave the US to find what I want.
Yep, that's exactly what I did. I'm in Tokyo now, and it's mostly what the "NotJustBikes" crowd is asking for: great public transit, walkability, lots of bike-riding, etc. I see kids walking or riding bikes by themselves all the time. I finally realized I was never going to be able to live in this kind of society in the US, so I found a place that had the lifestyle I wanted and moved there.
The helmet safety panic really crushed a lot of my enjoyment of life. Made riding a bike utterly miserable for me - both socially with my peer group at the time, as well as it being massively uncomfortable to wear. Not to mention getting in trouble dozens of times for leaving it at whatever location.
I usually would end up biking outside sight distance of the parents and ditch it under a bush for later retrieval. But once this rule was enforced on me, my biking was severely curtailed as it didn't have the same simple joy of freedom it had beforehand.