I have a friend who has a fairly small studio in Soho. The "living room" is reasonably large, but the sleeping area is an alcove with a mattress on the floor with a view of an airshaft, and the toilet and shower are in the kitchen which doubles as the foyer. Pretty shocking to anyone who has never lived in New York.
He lives there alone. In the 1870s, his studio would have been three separate tenement apartments, each one with multiple adults living there. Scary.
If we had a true housing free market, Harlem would be peppered with high rise condos convenient to shopping and mass transit, and commanding prices that would make most Americans swear the decimal was in the wrong place.