Safetyism is a contributing cause, but children have far fewer siblings than they used to. This means it's harder to go outside semi-supervised, and parents are more protective of their kids because there are fewer of them. Differences in reproductive strategies result in differences of parental care.
I'm a only child, and was a free-range/latch-key kid in the 80's. I'm thankful for my neighborhood friends, they were a excellent safety substitute for my non-existent siblings.
We lived on a somewhat quiet dead end street. The neighbor kids were fun but we got into all sorts of nonsense...
I have a very distinct memory of my parents taking me to go furniture shopping at about the age of 8 or 9. It was a fate worse than death. Do you have any idea how boring furniture is to a small child.
I remember coming home, rounding a curve on our street and seeing the end of it. SO. MANY. FIRETRUCKS.
I missed the roman candle fight, I missed the dry pine going up like a torch. I missed the fire department (small town they all came it was an even) and the police.
Dumb luck kept me out of a lot of trouble in my youth. it. It's no wonder im not dead.