100 years ago it was filled with warehouses and factories. Those all left and never came back, and they were renovated into housing and offices.
If the offices leave, all those buildings will be renovated into WeWork like spaces (if not WeWork itself) or into more housing. Especially if everyone is working from home, people will want bigger places to rent. A single person may want two or three bedrooms (one for them, one for the office, maybe one for a guest). Not everyone can or likes to work from home, so if offices start closing, a lot of people will still want an office like place to go to to get away from kids and family or just to get more space.
New York is still a cultural center. People will want to live there.