Actually, once the new NA and EU data centers are up, there will be plenty of houses to go around if people are willing to shift servers. We are already seeing empty wards in Materia even after the 1st round of lottery and it's going to be the same in the new NA and EU data centers.

Especially with the new data center travel implemented in patch 6.18, there's no reason not to move servers if you want a house and still want to see your friend.