Of course, they're very unlike each other. I'm just not convinced by the idea that a city needs poor (both in income and in quality) people in order to function

Of course, they're very unlike each other. I'm just not convinced by the idea that a city needs poor (both in income and in quality) people in order to function. The low-paid jobs which do need to be done in Manhattan can easily be done by people commuting in from New Jersey. I'm actually not sure about the outer boroughs, I've never actually been there (that sounds snobbier than it is, I've only been to NYC twice). It seems to me that gentrifying the outer boroughs should be one of the great challenges facing New York City.