That's only half of their response.

Yoshida: There's an issue where we won't be able to increase the amount of land if we allocate too much data resources to houses. Our plan is to first add as much land as we can. After this, we'd like players to build a lot of houses and once the needs of the players have been met we would like to increase the amount of items that can be placed. We are placing the highest priority on making it so a lot of players can possess a house, and then we will look into increase the amount of items that can be placed.

This shows that there's a hardware/software side to this that they need to deal with before they can make this happen.