Particularly in NYC you can’t just build housing - there’s nowhere to put it! The city is already incredibly dense and most land is already used for housing. Your best bet is demolishing lower rise buildings and replacing them with high rises.

Which, they do all the time, even in places like Brooklyn. It’s been happening for decades. But as you can imagine, it’s a long and arduous process. It’s not like erecting an apartment complex in the middle of a big plain of land in Texas.