> Kids cant play outside because the outside is filled with 2 tons killer machines i.e cars r/fuckcars r/bancars

Kids can't play outside because parents don't allow them to. Single childs were traditionally more protected once they are naturally considered more "precious" and they are slowly becoming the norm. Large family's kids still play outside specially the ones from poor families.

I meant play outside unsupervised like in the old days. Why don't parents allow them outside (unsupervised)? One big reason is due to cars(also due to over-hyped media stories about kidnapping). Think about it, would you let your kids play outside? If you dont have kids, trust me you wouldn't. Not to mention its not even legal anymore, social services get called if they see a 10 year old outside alone (UK where I live)

We raised our kids in a large city in America. Perhaps we just bypassed this trend but we totally let our kids play outside unsupervised. We set boundaries and taught them the necessary skills to do so safely but then we let the go and play. And we lived on a pretty busy street. There are age considerations of course and we had a large family for the time (5 kids) so there was a wide range of ages with the elder kids watching the younger ones.

Maye we are just outliers but I don't think the reason is necessarily cars.

Yes, there's a whole movement around Risky Play and not coddling your kids. https://www.nytimes.com/2020/07/21/parenting/risky-play.html

I have friends that bring their computer or ipad to the park and work while the kids play.

Some anecdata: where I live, gypsy and african descent kids play all afternoon (or all day during weekends and school holidays) outside with minor if any parents guidance. Other kids, rarely.