Well, regardless of the question whether it would be wise to go back home, I still see strong incentives for the girls to want to end the current situation.
First and foremost, harem porn game or not, fucking, eating and watching TV and reading books is not very exciting in the long run, especially if you have to wait your turn. People want goals or a purpose. Second, the people in this house have no control over their lives whatsoever. They are confined to a small space they cannot really leave. Even with your needs catered for this feels at best like being a pet of destiny.
This does not mean that they have to go back - but they would want the possibility or opportunity to go back. Then they can still decide to stay on as long as they can go back home (or a different, better, place) tomorrow. An ending with options (not for the player, for the characters) to "do as they please", including visiting each other and going places, regardless of whether they will actually do so. So both "stay in the house but visit the world(s)" (maybe not even limited to their own but we would need a reason) or "go back home each but visit each other when they want" would probably work. Them just staying there because they just cannot leave would be a bad ending in my book. Them staying there but they can leave tomorrow however, as some suggestions went, could work. Always stay one day more - in German (HansDampf may know it - the name sounds pretty German to me) there is a saying which translates "nothing holds as long as a makeshift solution".