I read a thing where they can do this with commercial buildings from before like 1950, but a lot of the big skyscrapers are harder. The older buildings have a smaller footprint, so it's easier to convert them to apartments with windows and a decent layout. When you convert the big buildings, you either end up with a bunch of really long, thin apartments with a window at one end and no natural light in the other rooms, which makes them unappealing; or you get a bunch of apartments clustered around the edges with all sorts of unused space in the center. You can convert the center space into functional space - storage units for the apartments, a gym, meeting rooms, etc - except then you're committing to higher costs for maintenance, cleaning, insurance, etc.

Personally, I'd like to see the second option become a thing, but then I don't own any large commercial real estate, so ...