Because content design and its release schedule often encourages players to take a break or step away from the game and housing is not only a limited resource but a massive investment.

The current endgame raid tier will have been out for 6-7+ months by the time Stormblood is released and outside of that there is very little content that requires a regular log in schedule for a long term reward, It's probably the game's largest flaw.

Especially now when we're looking at a 3 month no content stretch (outside of MSQ) until June.

This doesn't mean however that many of those players who own a house aren't interested in Stormblood when it comes out but they may have very little reason to actually log in and do anything else.

The game already punishes homeowners by mandating a recurring sub to even keep their property due to the poor implementation of player housing, why should they be forced to constantly play as well?