You don't know how much hardware is actually required nor how much a new system would get used (especially considering how many players would then have access to something they currently don't have).
By your definition, the current system is even less than optimal. Look at all that wasted server memory for the sake of a single player who happens to be standing alone in a ward compared to optimal use of that memory for instanced housing.
They don't need to create a completely new system from scratch. They can copy existing systems for a starting template and improve on those.
Not certain how the activities of a very tiny group of forum posters relates to developers working on improvements to housing system. I doubt that the team responsible for player character model customization also handles housing.
The developers working on PvP are most definitely not the developers working on housing.
Now this might actually a connection with housing as I imagine the UI team probably multi-tasks across different areas of the game. But then again depending on which route SE might choose for housing improvements, need for assistance from the UI team could be minimal if needed at all.
The developers working on gear are not the developers working on housing.
Why have the remade anything in the game? Because enough players were not happy with the existing version and requested improvements. Most jobs in the game play nothing like they did back in 2.0. Most of what's left is ability names.
Why should housing be the only thing in the game they're not allowed to update when there is such a demand for housing? Because it will infringe on the prestige you assume you have as a house owner?
And both FC rooms and apartments are included in the housing system of this game. You can't sit there screaming "they're not housing" when they are. It's not the lack of a feature that creates most of the difference between a house and an apartment, it's the quantity of the feature.
You're like a child screaming "that's not an ice cream sundae because it only has one scoop of ice cream and is missing the cherry on the top". As long as it's got the ice cream and some sort of toppings that include a sauce, it's an ice cream sundae. Apartments are still housing because they have the base qualities of housing (a place reserved for the player that the player can customize to create a home for their character).
Trying to redefine the word to suit your goals isn't going to get you anywhere.
Again, you should be describing what you want from housing, how a house provides that something and how an apartment does not instead of stamping your verbal feet going "apartments aren't housing!"