Parts of the country are seeing a revival of manufacturing — traditionally a source of upward mobility for immigrants — but not New York City, where manufacturing continues to decline. The culprits here include the city’s zoning policies, business taxes and decaying physical infrastructure.

Then there’s the cost of living in New York City. A 2009 report by the Center for an Urban Future found that “a New Yorker would have to make $123,322 a year to have the same standard of living as someone making $50,000 in Houston. In Manhattan, a $60,000 salary is equivalent to someone making $26,092 in Atlanta.” Even Queens, the report found, is the fifth most expensive urban area in the country.

The implications of Gotham’s “hourglass economy” — with all the action on the top and the bottom and not much in the middle — are daunting.