Perhaps I'm too high on sci-fi. But I'd imagine office and retail would work well enough. Put in artificial sunlight, channel some light from the roof area, run large displays to simulate outdoors. If it really works well, then residential might work, too.

And fighting over real window space is a far cry better than fighting over any space. As-is, there are even parking garages taking up nice window space in buildings here.

The geography looks a bit hilly in SF; it might be cheaper to dig under those hills than just going straight down from a flat area.

Maybe I'm just completely naive, but anything seems better than the current solution of doing nothing.

More importantly, building down has geometric levels of cost and linear levels of return.