> What you are describing has only been my experience in suburbia. Major cities are a lot more walkable as far as getting to a grocery store or convenience shop or whatever.
The problem of course, is that almost all American cities outside of a small handful are effectively a tiny downtown core surrounded by what amounts to suburbs. Only a few cities such as NYC, Boston, Chicago, etc. really qualify as "city living" in the sense you write above - being able to quickly and easily take care of your day to day needs within the neighborhood and thus resulting in a wildly different lifestyle/culture than the suburbs.
I've lived in a number of places, Chicago is where I currently call home. The lifestyle of living 2 miles from downtown Chicago vs. the Chicago suburbs is a night and day difference. Living 2 miles from downtown in Minneapolis is effectively no different than living 30 miles out in the exurbs, even with sidewalks and grid layouts.
As I get older I see "suburbs" to be a lifestyle more than a description of urban density. While not perfect, my quick rule of thumb is that if the average person requires a car to effectively participate in society - it's a suburb, not a city.
The more time I spend living in European cities really drives this point home to me. Sprawl has totally, completely, and irreversibly changed American culture for better or worse in very deep and subtle ways.