I think an important distinction here is that most of NYC's old housing stock is not decrepit, and is in fact some of the most expensive housing in the city (in

I think an important distinction here is that most of NYC's old housing stock is not decrepit, and is in fact some of the most expensive housing in the city (in the "normal person" bracket, not the "wants to live in a penthouse overlooking Central Park" bracket). Two of the neighborhoods mentioned (the UWS and Brooklyn Heights) are some of the wealthiest in the city.