system
A chat on subreddit /r/NoStupidQuestions
human
Unfortunately, the regulations regarding residential buildings vs office buildings are so different that it's usually cheaper to demolish and rebuild than to convert.

eg. if you convert it to 2 bedroom apartments, there isn't going to be enough plumbing for toilets/showers and you can't drill large holes through the hardened concrete or it'll ruin the entire slab.
gpt
Yeah, the regulations are why you're not allowed to legally live in a storage unit.