I think the problem with your thought is that it really requires a "stars to align perfectly" kind of thing for that to actually be achieved, especially over the long-term.

Many people had that sort of experience in say....the 1950-2000. You had a lot of smaller new developments bulldozed into new areas, and for the first 20 years especially - almost everyone who moved in to those new homes, moved in at a similar time and with young children of a similar age.

In this way, those pockets of suburbia had a bunch of temporary features. You had a much higher quantity of local children within walking distance than would naturally be the case in the long-term for that number of mid-sized SFH homes, and you had a highly developed area with a highly undeveloped area nearby. (land not yet turned into subdivisions like your own).

But a few decades down the line, even without the large behavioral shifts in society - now you've got an endless sea of divided-up suburbia with no nearby wilderness accessible by children on foot/bike, and there's only 2 nearby kids of the same age range rather than 20.

Which is to say - I think it's very difficult to achieve that as as a stable long-term environment, at least with the typical US SFH subdivision density.

And once you get out to rural you run into the problem of the kids not being able to see each other without parental involvement.

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Anyway, I did grow up in a "goldlocks zone" environment like you describe. It was very nice, and I was particularly adventurous + had more relaxed than average parents.

But I actually found in (Upstate NY) college that the kids who had the most similar levels of life experience to me were the...NYC kids. The city enabled and outright required them to be much more independent than the more normal US suburb experience was. They'd be taking transit all over the city, many even just to get to school by middle/high school - and then after school they'd be going out with their friends to get snacks or hang out in the park or whatever.

In contrast, many of the "average" suburb peers had basically never been able to go a single place in their lives without an adult driving them until maybe they got a license at 16-17 and seemed very limited in their development for it.

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tl;dr - I think the idealized version of a suburb can be good for it, the average US suburb can't stay that way, but I also think major cities offer a lot of potential for them. Denser + walkable medium towns + nature outside them could also be good - but that's more of a EU than US development pattern.