Building underground is much more expensive than building up.

I lived in NYC until very recently and was kinda sorta apartment shopping. One place I looked at had the common areas on the ground floor, the bedrooms on floor -1 (with small windows that looked up to grates through holes in the ground) and then a windowless basement on floor -2.

It was kind of neat actually and pretty cheap (relative to similarly sized places in the neighborhood) due to being on the ground floor and below.

Isn't there some kind of law against a living space without access to windows?

I'm all for the idea, but I don't get claustrophobic very easy

So, making underground excavations in one of the most built up pieces of land on Earth. Doing that safely would cost a pretty good penny, so you'd have to sell them as "luxury" condos, but who in their right mind would spend that kind of money on a windowless hole, rather than living a bit further on a regular condo?

I'd bet zoning is not the only thing keeping that from happening.

The water table is a pretty obvious barrier to that in all 3 cities you mentioned.

> -100 stores underground in NYC or LA or SF

I don't know about NYC but California is an earthquake-prone area. Making underground housing that can withstand a serious quake would be quite a challenge. And imagine trying to rescue people from -100th floor after one...