I lived in a rent-controlled apartment in the 1980s and it was impossible to get the landlord to fix anything (i.e. invest in anything) regardless of what the laws said (this was Cambridge, MA, and the usual junk grad student apartments next to campus). He wasn't going to get any additional rent for anything put into the building.

In fact his best option was to let the block decay and become uninhabitable so he could pull it down, put up something better, and rent out at market rates to new tenants. A few years back I drove down the street and guess what: the buildings on that street had clearly been built since I graduated.