[dagw]

It's not as if we could leave out sprinklers and fire escapes from buildings, and all of a sudden, housing would be cheap.

There's a lot more to fire codes than just sprinklers and fire escapes. If you could ignore all fire codes (and related requirements) then it would definitely be possible to build both more and cheaper apartments than you can now. Not saying it's necessarily a good idea, and they almost certainly wouldn't be nice places to live. But a lot of people would take unsafe, uncomfortable and affordable over safe, comfortable and completely unaffordable.

[kube-system]

They'd be slightly cheaper and wildly more dangerous.

But given the demand inelasticity for housing, it's not even guaranteed it would be cheaper.