Crafting, combat, and time also produce gil. I still think the fix is putting ARR prices back. 40m small, 200m medium, 500m large. Those were the original prices.

Players: Please, cheaper!
Yoshi P: The rich will buy entire wards, then
Players: Please!

We literally begged devs for the system we have currently. This suggestion seems sort of in spirit with bringing the prices back up, so that essentially players 1-5 months old aren't competing for houses with 6-18 months old players. Unfortunately, I don't see an entirely new housing only currency being programmed in, any more than an instanced housing system.