Reasons housing is coveted so much

1. It's a limited resource
2. Ppl think they can immediately plop a gardening plot down and it will instantly start printing money.
3. Ppl wanted private FC's so they could use the FC workshop as a personal source of gil generation.
4. Game lacks gil sinks that remove gil from the game by having players exchange it with an NPC. The cause of game economy inflation is gil is created by players exponentially faster than the few sinks in game can remove it.
5. There are larger FCs that actually do social things at their FC house
6. Some ppl enjoy decorating a house and having a place that suits their personal style and taste.
7. Some ppl want someplace to stick all those seasonal and quest reward furnishings, decorations, and food settings.

One of the things SE could do to noticeably reduce housing demand is introduce stronger and more meaningful gil sinks into the game so less ppl are just sitting on millions or billions of gil with nothing to spend it on.

And before ppl start doing 1 line posts of "Add instanced housing" how about actually plan out all the logistics of adding said feature before throwing it out there like it's just a matter of a fairy waving a wand and poof it happens.