Space is limited, a large part of the housing stock is under rent control which drives up the price of all other property, and there is extremely strong demand. Also, all the goods you buy in NYC - from groceries, to clothes, to alcohol are expensively imported into the city in small, inefficient batches (usually by van or box truck), since there are no freight hubs or major shipping facilities in Manhattan - despite the fact that both these amenities would be very easy establish.
Also the taxes - income, sales and real estate - going thru the roof under the Dems.
There’s that and there’s also tons of foreign/tourist dollars pouring into the city which creates a surplus of dollars that translates into higher prices just as it does in Disney land for example. I have to wonder if what organized crime doesn’t have a hand in it too by taking a cut of everything.