tldrIt's absolutely to force people to stay subbed. If you don't pay your rent IRL you get evicted as well. Apartments (and now islands for outdoor furnishings), are the better choice for someone who does not plan to stay subbed perpetually.
Also remember that FC houses only require at least one member to walk in every 45 days; if they get demolished it means that every member of that FC has stopped playing.
Regarding the "manual labor" comment for new housing wards: It's not that. It that it takes up server resources.
Because of their blasted neighborhood ward design, all neighborhoods must exist in the live RAM of the world server so that people can hop into it in real time and see everyone else's houses in real time. Even the interior of your houses are technically one giant zone within the perpetual neighborhood space (as we found out with the log out workaround where people would initiate crafting inside their houses to avoid getting kicked out during 5.0 launch, and thus block anyone else from entering the interior of the housing zone because the zone was full!)
This means that every new ward added increases the live world server overhead. They've managed some pretty neat optimization tricks over the years to pack as many people onto each server as possible, but there is still a finite amount of storage space in RAM on a server, with most lower end standard configurations topping out at 128 GB of live RAM and the highest end of corporate servers reaching 12TB. I do not think that SE is using the latter kind of server, but I would suspect their world server data still isn't going much beyond 1TB per world, with another 1 TB per instance server. Maybe it's 128GB on the lobby server since that server doesn't have any persistent live data to deal with, just the lobby queues.
Apartments and FC rooms, on the other hand, are purely on demand instances, like duties are. They are stored as data and recreated in real time whenever someone chooses to enter them. Its the same with the Island Sanctuaries. It's a much better system since the location is only added to the instance (and thus the server RAM) when someone chooses to initiate it.
"poor square enix they are such a small indie company they cant afford proper servers"
also lol @ comparing this to IRL rent, like really ? Lmao