So many possible factors. Family support allowing more sleep, less car-centric cities, less tradition of single parent transporting the kid around while on errands, etc etc.
The US is entirely built around car culture. Chances are you don’t get in a car for everywhere you go. In the US getting in a car to go virtually anywhere is unavoidable. This is a tiny percentage we just have so many more car trips per day than most countries.
Edit: fixing counties to countries cause autocorrect.
Let's name a country. Let's do a 1:1 comparison. I bet we can identify more logical factors than the whimsical notions of, "brain rot." I bet we can also peel back some not-so-comfortable factoids about said country, too.