Matt Yglesias comments on US cities leading in construction spending. New York is not only way ahead, it's an outrider way ahead (though not quite at a Pareto distribution -- construction is expensive here, so that may be why there's no Pareto), and it's not correlated (pace Yglesias) with population; LA is next most populous, Chicago, then Houston, all on a Pareto distribution, but LA is low on construction; Dallas is constructing more than Houston even though Dallas doesn't have much more than half Houston's population size. In fact Dallas is about one seventh the size of NYC, but it's constructing at the absolute rate of 60% of NYC's.
In any case, NYC is booming. Given the high cost of construction in NYC, this boom means developers see huge money in development. How much of that do you think is affordable housing?
It also means that developers are not worried about diluting the luxury market. Why? Do they expect high-renters/owners to abandon older housing stock to move into new? Or locations further from the center into closer? Either of those would be good news for low-income neighborhoods -- less displacement pressure on them. But if developers simply expect more high-paying population in the city, then no one benefits but the developers.