“Oh they’re too wide and you’ll have to make the units narrow strips that only have a tiny sliver of window on one side” Do that then.

Some people would be willing to live like that. But the rents per ft^2 or m^2 would be abysmally low. And renovating the buildings would still be very expensive. It may be physically possible to turn those deep floor plate cube farm skyscrapers into housing, but it isn't financially possible. The money would be better spent tearing the buildings down entirely and just building entirely new residential buildings from scratch.