I don’t believe only girls can have dollhouses. My husband calls the ones he built for our sons when they were 3, “architectural models”. I find it easier to say dollhouse.
One of my sons kept his house neat and orderly for a while and “played house”. My other son liked to mess up his house and store some of his stuffed animals in it. Since my boys are twins and share a room, I think it gives them a good opportunity to make their own decisions about personal space – no sharing and no debating about how to use their own houses. Now one is painted green and the other is blue.
Over time, the dollhouses get played with for many days in a row or they may sit idle for long time periods – it all depends on the interest of the moment.
Recently my son decided his house is a cool place for his Batman and Robin toys to visit. Now the house is the hub of superhero adventures…