There's a limit to how many houses a single service account can own on a server: 1 personal house and 8 FC houses.
In order to own more, a player would have to get more accounts and pay the subscriptions.
~70% of the houses on NA servers are owned as personals.
Secondly, the majority of gil rich players are not motivated enough or have the time to grind out the gil and other requirements to owning that many houses.
Right now we have a situation where any new player fresh from MSQ with 3-5m can buy a small house.
Meaning the pool of competitors for a small plot is vast. If house prices were higher, there would be less people camping. The people who can't afford a house can wait for the devaluation timer to reduce the price and grind out gil in the meantime.
Adding new wards does not solve the problem,it merely kicks the can down the road; there are not enough houses for every individual player in NA servers especially if player populations keep increasing.
Upgradeable apartments for gil with balconies for gardening/delinking the FC workshop from ward housing would go a long way in reducing the demand for ward housing.