I live in an area of the US that the vast majority of US citizens would describe as "city" yet it doesn't conform to your description. The kids here get along just fine. But it's an important distinction because it would have been described as more of a suburb 100 years ago in that we are a few miles away from the heart of downtown.
But a lot of people will pop up and say that 80% of the US is urban with the implication that 20% of people are living in the back of beyond in Wyoming and it's simply not true.
My daughter has slept under the shark tank at the aquarium as well as with the mummies at the local cultural museum. The local university runs summer camps for everything from engineering to gymnastics. The Museums run programs, too. Her grade school has a thriving parent community because the parents stand together when school is let out instead of forming a long line of cars, I've made new friends myself this way (the number one complaint I get from parents that do move out is that they know no other parents in their kid's school). Because I walk everywhere, I don't ever deal with traffic.
I'm not saying it's perfect, either. Urban areas vary a LOT, including within any single city and within the country. My child's been directly exposed to poverty, homelessness and mental health issues, etc. I'm comfortable enough to explain the complexities of this to her, but some people would rather not.
This is not to criticize people who want to live in a rural or suburban life. I grew up in a small town and got myself out of there very quickly, mostly because I felt isolated and trapped growing up. But cities are very much places you can live in, kids and all.