For buildings where they can't cut the whole center of the building... maybe cutting more (but smaller) holes part way between the outside and the center would work. Then do vertical gardens up those shafts.
The issue is emergency egress. You need those shafts to be able to support external staircases with many dozens of people rushing down simultaneously in the event of a fire.
No, the window requirement is another housing suppression tactic. In New York, it is common for apartments to be illegally subdivided. It's how a lot of people live because it's affordable. I've done it. It's fine.
Stairwells are necessary. But nobody on the 60th story of a high rise is egressing externally, FDNY's ladders don't even go that high. If you're only home at night, the window is a luxury. As evidenced by, when people are given a choice between more cash and a window, many choosing the cash.
I believe there are two different requirements for residential: 1 is egress (fire regulations), and the other is natural light requirements for each room.
