It’s not a complete reversal, but the fact that Japan’s rising birth rate has defied regional and global trends and persists despite continued urbanization and secularization shows they might be on to something.
Culture matters, and quite frankly Japanese culture is different.
Public transit? Most everyone in cities that really depend on it like NYC.
Middle school kids taking public transit by themselves is pretty normal.
I feel like there's basically a two-generation swath where kids were treated like they'd break if you breathed on them, which coincides with the first generation that's never known real deprivation (Boomers) raising kids in an environment where their leaders are trying their hardest to create an environment of fear to maintain social control in the absence of war and real deprivation. It's slowly reversing itself as Millenials are themselves having kids and realizing all the ways that they were screwed over by not being forced to face risk & adversity in their formative years. (There's a big selection bias, too, in that Millenials who buy into the culture of fear are just not having kids because they think the world is hopeless, meaning everyone who has a next generation tends towards the un-anxious population.)
If you go back to the 1980s, what she did wouldn't have been that remarkable. In that time, kids like me were gone from home for hours, walking or riding bikes for miles away from home, and we didn't have cellphones for our parents to keep tabs on us. Statistics show that crime rates were much higher (they peaked in the mid-70s, and have been falling since); the difference is that Americans just weren't paranoid back then the way they are now.
(Also stranger danger is overstated, most victims know their assailant, etc. etc.)
There are various historical factors that have resulted in that abysmal situation in the US. Assigning it all to a four-word summary of Japanese culture is a bit reductive. The dangers in the city are different than they in the 80's, and they'll change again. The important part is to believe we can do better.
In major American cities, kids are taken on public transportation all the time. Often big groups of school kids are in transit for a museum field trip downtown.
Homogenity has little to do with it. Same paranoia is applied to playground structures, when the child can stay alone home for 1 hour, to everything.
America (just as most developed nations) only props up their birth rate though immigration.
Of course, Japanese cities don't have enormous parking lots, everyone driving cars, etc. They have taxis of course, and some cars (not a lot really, given the population), and work vehicles, but not the huge amount of vehicle traffic we have. And of course, there's tons of trains and buses, so it's really cheap and easy to get around by public transit. On top of that, there's bicycles: tons of people get around by bicycle, and the traffic level and speeds are low enough to make this very safe, plus there's no culture there of being aggressive towards cyclists or pedestrians the way America has.