You can't take the existing housing and make it instanced. It's literally built around the idea of neighborhoods, and so each housing ward is a zone instance. To instance the existing housing you'd have to junk the entire system, and that's not going to happen. What is going to happen is that they will be adding approximately 512 instanced private apartments or condominiums to each housing ward/sub-division via a new form of instanced personal housing. Think of it like an enhanced version of the FC personal Chambers. With that addition and a new housing area based (presumably) in one of the Heavensward zones (connected to Ishgard), there should be housing for all, with housing for all manner of budget also.
Then read my comment and you'll see that instanced housing and a completely new housing area are coming to the game. I've played since Beta phase 3, and I was fortunate enough to save sufficient gil to obtain a plot when the first wave of auto-demolition happened. It cost me a night's sleep, but patience paid off. I realize that the supply is limited, but for anyone that has been waiting for 3 years, there have been opportunities to obtain housing. However, fortune may not have smiled on you. In which case, I would hope that some of the upcoming additions to housing will help.
