They would have to make it a player hosted instance. There's no way in hell they are going to have servers capable of supporting that many houses even small ones. They know it, we know it, everyone knows it. They just wont admitt it. White knight chronicles did this system the best way. They can keep their server instances, those houses can be more expensive for it. I just want to be able to host my own instanced house.

As a last alternative, the only way they could do this for everyone "who really wants it," they would have to charge a monthly fee similar to retainers which many people would fuss worse over.
Ultimately best possible scenario is player hosted... if you have terrible internet or live in a third world country, its your problem then.