That or limit it to being outside a certain radius, so you can have your house in the city and a second property out in the woods for the weekend as long as it's, for example, 50 miles away or more and then if you want a third property it needs to be at least 50 miles away from the other two and so on. Make it impractical enough that second properties are only cottages, not rental units in the same city.
Why do you think I'm joking? People should be allowed to own something out of town for the weekend if they want but they'll think about it twice if they can't own both a rental unit and their main house in the same city, in the end it will force them to live in their rental unit along with the people renting from them, forcing them to actually care for their property.
They won't want to own a shit load of properties either because maintaining then will be too impractical as none of them are close to one another.
Or control the type of ownership based on the number of doors. 1 to 4 doors > private ownership. 5 to 8 doors > corporation or cooperatives. 9 doors or more > cooperatives/non profit/State corporation.
Which they are already doing everywhere in my area. I’d say we should also limit their ownership of apartment complexes. Though that’s a tougher problem to solve.
SF Bay Area, East bay. Everything is apartments. Seems like all new developments are apartments, not houses. And obviously those will be owned by corporations.