Why? The landlords are providing a service, in the form of maintenance and flexibility (you’re not tied down by a property that you own if you don’t want to stay in a given place for years on end). For providing that service, we should be entitled to a profit.
Or do you also subscribe to the horseshit that supermarkets are “monopolizing a basic necessity” by selling food at a profit? Or how about car leasing agencies, that “monopolize transportation?” Yep. Clearly.
As far as tax revenues — if most properties are forced back into owner occupancy, then revenue increase will not be as predicted since the mix of properties will have changed.