Where do the children play?

As a parent, I relate to all this. Great piece.

When the kids were babies we had the standard debate of move to the countryside for fresh air and gambolling in the fields etc. But so glad we stayed in London, the kids have so much freedom with public transport they can organise their own meet ups and activities and go running around all over town without any parental assistance or intervention at all. Whereas elsewhere we'd need to drive them everywhere, they'd be stuck at home way more, they'd have no real agency in their lives - I grew up like that and hated it.

There's a middle-ground between a big city and full countryside.

I lived my childhood in a place with about 4000 people in it. School, friends and everything else I needed was within walking, or at least biking distance. My parents didn't have to drive me everywhere. Obviously there weren't as many possible hobbies and events as in big cities, but mobility wasn't an issue.

Right. Most people in "rural" places live in small towns. My wife went to high school in a rural Iowa town with 2,000 people. You can walk from the high school to anywhere in town in 30 minutes.