That's massively over-generalized. I live in Pittsburgh, which is not a huge city, but my experience is the exact opposite. My 8yo walks to friends houses in the neighborhood and to the park by himself sometimes. My 13yo is now switching from private school to the public high school, which is quite well-regarded. We don't live downtown, but our part of town has been an amazing place to raise kids. (Squirrel Hill, for those stalking Pittsburgh remotely. :). We chose not to live in the bars and parties areas because we're not 20. Cities are not homogeneous.