you can't both expect profit and good maintenance. pick one, or the other. in all things. that's why roads aren't privatized. or the fire brigade. etc.
I care less about the number of units the landord has(within reason) than where they live. If a guy wants to rent a dozen units a few blocks from his own house, fine. But some asshole 5 states away renting a house he's never going to lay eyes on? Fuck off.
I'm not saying local landlords will necesarily be good landlords, I just want them within the jurisdiction they rent in. I want the people they know irl to know they're assholes and slumlords. I want the local news to be able to stop by their house and ask them why they suck. I want the people who live in their rentals to take all that shit to the same local government they have to deal with for anything they want to do apart from runing rentals.
Housing needs to be about housing, healthcare needs to focus on healthcare.
That's why I think profit needs to be eliminated from the equation. With it, the priority will always be maximizing profit, with providing a quality product or service being secondary, or even incidental.