I don't know. Maybe this is going away in some places, maybe I just have my own anecdata, but my kids play outside unsupervised all the time, as do all the kids in my neighborhood. I live in just a regular suburban neighborhood on the outskirts of small Metro. Nothing special about it at all. Every time I see one of these articles I always wonder who they're talking about. I always feel like this is just one of those…
This behavior is probably overrepresented in the bougie places reporters live. I dropped my daughter off at the mall to hang out with their friends and one of the moms followed them around the whole time. They're all 13!
One would expect that after your first sentence, the second sentence would be a counterexample.