There are less obvious costs to living outside a city, especially if the city has transit. All the car costs, for one relevant example. The health loss from walking less. The isolation takes a toll. The shallower social pool. Fewer cultural options.

Also it's not like apartments are dirt cheap in the suburbs outside NYC. I could pay $2000/mo for a nice apartment in Plainsfield, NJ... or I could pay a similar amount, not have a car, and live someplace where stuff happens.