I think you're referring to this dev quote:
That quote was in a discussion of them adding more wards. And he was comparing the difference between an inn room and a housing ward in that the inn rooms have no saved items and if it does, it would be same as adding more wards (land). Not that it was the reason they don't have instanced housing.Finally, I’ve seen a few posts on the forums saying housing would be better if it was instanced like inn rooms are, so I want to point out that instances aren’t saved. Nothing in an inn room needs to be saved; player housing, on the other hand, necessitates personal save data for things like furniture placement and character location. So, it would really amount to adding more land anyway.
And not sure if you read the rest of my post instead of stopping at the first sentence of which you quoted, you would notice that i was talking about "individually instanced" housing.
Right now, they have 30 combined houses per ward (instance) and the problem with that is if there are hypothetically 20 unused houses regardless if it's bought but unused or available for purchase (plots), it still takes up server resources because it needs to be loaded by the server all the same...AND still limits the number of housing items people can add because SE has to account for the possibility of 30 houses having max items whether it happens or not. Not to mention, it limits housing upgrades (small > medium > large) because it's fixed. All you're doing when you upgrade (now or after they add a move option) is shifting your coordinates in a similarly limited fixed map.
If they switch to individually instanced housing, already it would use up less server resources because you don't have to load UNSOLD plots until someone actually buys it. You also only have 1 person/group's house to compensate for the number of items you can add instead of 30. And if 20 houses are bought but unused, they can be unloaded to free up server processes and have the added benefit of not aggravated players if they decide to come back since it doesn't need to be deleted.
Relinquishing inactive houses will not stop land baron players who buy houses with intent on reselling. All that would do is make them visit their house once a month or however long the inactivity timer is.
I've already mentioned invidividually instanced housing examples in Wildstar and Black Desert and those aren't even the only ones that have that type of system.
Unless you're saying everybody else is capable of doing this except for SE who seem to be inept in proper mmo scalability design concepts?
I believe Yoshi just wants a neighborhood set up but don't have the infrastructure to handle it. And that is a similar mistake with not instancing the persistant zones. Remember what happened when they launched gold saucer? People getting locked out because the zone was full. It wasn't until Heavensward (almost 2 years later) when SE finally gave into instancing zones (hw ones anyway) to be more scalable to player use.
(Eventhough they couldn't do that properly either with separating teams into separate instances and not have an option to switch back without running in and out of a zone.) But that's another topic for another time.