That is if you don't renovate nor modernise the building at all. It is an incentive for landlords to keep the building up to date. In your corner case scenario,

That is if you don't renovate nor modernise the building at all. It is an incentive for landlords to keep the building up to date. In your corner case scenario, an outdated 100 years old apartment would be pretty lame and worth its fair price of "almost free".