In some places where control has become onerous, owners simply walk away from buildings at some point, leaving them to decay as they will.RichardR said:To a minimal level, yes. No laws force property owners to improve their buildings, though.
I'll take your word on that regarding California. That's not the case in some states, or at least municipalities, if the improvements relate to fire, electrical, heating, or plumbing safety.
Note, I'm not talking about replacing unsafe or malfunctioning systems, either, I'm talking about installing new stuff based on the fears of tenants.
Rent control laws, however, may cause some property owners from putting off some essential repairs. That's wrong, of course, but it is a possible consequence or rent control.
Parts of NYC were having that problem for quite a while. I'm not sure how it's resolved lately, having moved 2996 miles west of there.