This is an indirect way to get at what we really need: a wealth tax. Don't treat the symptom, treat the disease.

Or unoccupancy tax. Forcing landlords to let at the price renters are willing to give will probably do some to reduce rent levels.

Same goes for commercial, but in that case, I'd even suggest forefeiture if you are not reducing requested rent within a year of vacancy. Let someone else take over if you overspent.