You can put limits on rent increases through many means. For example limiting the increases per year, and limiting increases to when the landlord actually impro

You can put limits on rent increases through many means. For example limiting the increases per year, and limiting increases to when the landlord actually improves the building (with concent of the occupants). You can put taxes on landlords, you can ban things like AirBNB. You can make many areas nice to live in. You can construct affordable housing. You can make it almost impossible for landlords to evict tenants. There's lots of other ways that are used too.