But the Netherlands, Nordics and Germany are still very much on the other side of the spectrum in these studies.
See for instance the books "The Happiest Kids in the World", "Achtung Baby" and "There is No Such Thing as Bad Weather" about raising children in the Netherlands, Berlin and Sweden respectively.
Those places are very much not like the USA yet. Though as the article points out, they are definitely going in that direction.
That being said, obviously mobile phones etc are huge and (in my opinion) problematic among kids here, too.
[1]: https://www.reddit.com/r/Svenska/comments/vj2630/no_such_thi...
In the Netherlands, some things are trending in that direction (e.g. car sizes/hood heights), but I wouldn't call it a general trend; infrastructure, for one, is still massively improving. Where it was bicycle-friendly twenty years ago, it's way more so today, and bound to be even more so tomorrow.
The Netherlands is in danger of resting on its laurels and getting complacent. Some places (Hilversum comes to mind) are still quite mediocre.
Sometimes the kids walk alone, sometimes they pickup friends en route, or they have to take a bus/tram.