Have things really changed so quickly? 15 years ago, basically all the boys in the neighborhood would hang out in the woods and catch frogs and whatnot. That said, I grew up in a safe neighborhood, so maybe it depends on the area.

I grew up going freely by myself most of the time, since I was 6/7 - even going to school (in ex-communist Bulgaria). Then in 1999 came to the US (Los Angeles), and start seeing the difference. But my first boss, who introduced me well to the society told me it wasn't so. He was growing up in the Valley (San Fernando) and going biking to school every day for miles. Also if you check the 80s movies - E.T., Goonies, and even now Stranger Things showing how it used to be - kids really used to roam the streets with bikes (same was in Bulgaria too - most of our kids movies were about parents going to the beach in the Summer, and kids in groups strolling around). Or my favourite kids' show - Verano Azul (spanish, and very popular in Bulgaria back in the days) - https://en.wikipedia.org/wiki/Verano_azul - same thing - something changed much much later...

I’m a millennial and free range parenting wasn’t a term when I was growing up in American suburbs. I’m not sure what the norms are now. Seems to be a complete 180 degree shift that I don't think came from an even lower trust society than before.

I grew up in the 90s in a low-density suburb in Michigan and was allowed to bicycle around the neighborhood and hang out with other kids (although, I was also pretty introverted and usually not interested in that). I rode a school bus to school along with most of my classmates. That said, access to things like nature, shops and restaurants, and the library all required a car - not being able to access those independently made me feel somewhat restricted compared to how my parents described their childhoods (dad in a walkable college town, mom in a rural area where kids played in the woods) and compared to kids I read about in books.

One very noticeable recent-ish norm shift seems to be parents dropping off and picking up elementary and middle-school age kids at school. I don't know exactly when the trend started, but it seemed to hit critical mass after 9/11, and over the course of the following decade seemed to become the norm to the extent that suburban schools started remodeling their grounds and parking lots to accommodate a waiting line of parents in cars - something I've seen now in multiple states.