I am really curious if we had an up or down vote whether people would pass a law saying that everyone 12 and under must be supervised. I think it would pass.
I certainly wasn't permitted to walk anywhere by myself at that age, nor were any of the non-immigrant friends that I know. My sister wasn't permitted to do that until around 15.
As a boy in the early 80s age 10 in an American suburb, I rode my bike to school one mile and back. It was fairly safe.
I also walked half a mile to a school bus stop when I was 12 and waited there (on a pretty busy street - not sure if that makes it safer or more dangerous but I would guess actually safer.)
I don't think the risks were high then, nor are they now. But the culture of what is considered acceptable for your kids to do by themselves outside the home is definitely way different.
If I had to pick one factor that is different and driving the difference, I think it's that the society now keeps (public) databases of where sexual offenders live so the awareness of the threat is much more concrete, even if it is not particularly elevated. We are over-managing/weighting what we can measure.
But also feeding the changing dynamic is bureaucracy and funding and legislation reflecting both the wealth and fears of our society -- today I learned) Child Protective Services wasn't really created until certain 1974 federal funding was given to the states, and other legislation around this didn't come till the 1988 Child Abuse Prevention, Adoption, and Family Services Act.
I certainly wasn't permitted to walk anywhere by myself at that age, nor were any of the non-immigrant friends that I know. My sister wasn't permitted to do that until around 15.