I addressed your point ("guarantee that rental property goes straight toward ghetto condition as it would not allow for improvements and maintenance.") a dozen times, and refuted it entirely.
Whatever make you feel superior. Capping rent increases means landlords will either let them fall down or convert them to high end units, the latter of which is precisely why California's housing caps have shortened the supply of affordable housing even further. And none of that changes that real estate is not interstate in any remote sense of the word. The SCOTUS would smack that thing down in short order assuming The Furor could even get it passed, which he won't in his 6 months left in office.