There is also a gradient of density and walk/bike-ability between NYC, one of the densest cities in the country, and super spread-out car-dependent cul-de-sac suburbs, but the US often skips those middle steps.
Small towns where your kids can get to their friend's house by walking or biking a couple of blocks over can be great for raising a family, as opposed to all of their friends' houses being in a different gated communities up and down a 4-lane 45mph highway and where the line of cars picking up kids from school each day backs out onto the road and blocks traffic.
They exist, but in New Jersey -- most of the "cities" (with the exception of downtown Jersey City and downtown Newark) would be called streetcar suburbs in an earlier time. I live in one of them, and it's great: I have a small, private backyard, but I'm also <15 minutes on foot from multiple public parks, restaurants, shops, etc.
Sadly, it's illegal to build streetcar suburbs in most of the US today, because outfitting every house with a private driveway, setbacks, etc., would move everything far apart enough to significantly hurt walkability.
And the cost to buy into these developments where they do exist suggests a supply and demand imbalance. Near me a new-ish 'town center' development with a mix of apartments, shops, restaurants, grocery store, townhouses, and single-family homes is easily double or triple the price of an equivalent house in a standard cul-de-sac neighborhood a 15 minute drive away.