They mean more Americans.<p>For example, New Jersey has a number of smaller cities (Newark, Paterson, Passaic, Trenton, Camden, etc) in close proximity to major metro areas (NYC, Philadelphia) that suffered debilitating white flight a generation ago.  These cities are still economically depressed and are mostly inhabited by non-whites and tend to have lower incomes.<p>As much as the majority here seems to be extolling the virtues of urbanization, the real challenge are cities like this: what are currently barely-functional city cores that must be rehabilitated without substantially displacing current residents.