I count myself as a parent to two well-adjusted people now in their mid-20s (weird to write that down!) My siblings and I were typically free-range for the 1960s-1980s, and our kids were more free-range than their peers. So I'm mostly in sympathy with the writer's points. However, this is the internet where I always think of counterexamples.

I was a little girls' ice hockey coach for many years. People who reminisced about how much "nicer" it was in the days when kids could head off alone to the outdoor rink in the park and play all Saturday without adult interference forgot a few things. They forgot that in those days the girls weren't allowed to play, that the poor skaters and the weird kids didn't get much chance either, and that every now and then someone needed stitches or a plaster cast, or lost a tooth or worse. While the modern scheduled version of ice hockey is time-consuming and expensive for families, we were able to offer kids an experience that generally matched our modern values of being inclusive, supportive, educational, physically safe, and free of bullying, harrassment, or sexual abuse.