I’d love to have the functionality back for renting. It’s been a while since I’ve played any of the past games but if I recall correctly, a lot of the “This room/house/apartment belongs to X” was tied to special doors that work somewhat like club doors do now. I don’t think rentable rooms/apartments/dorms etc would be too hard to implement with a combination of special doors and lot types. A lot to designate the structure houses rentable space, and a door to tie specific sims to each entry. What would take extra code would be the payment process for renting and time limits where applicable.
Who knows, we may eventually see this functionality. They’ve been extremely slow when it comes to adding more complex interactions with objects. ??♀️