When I was young, most families lived in houses that had one bathroom. Nowadays, even apartments have multiple full bathrooms.
Im in a half trundled down farm house the size of a small mansion.
It has at least two mansions worth of good junk in it because the wife decorates in a very sheclectic style. She clects the crap and it just keeps piling up. I tell the kids its their inheritance.
Anyway, it was designed sort of as a duplex back in the days when people had a pile of kids. Its from a time before retirement and nursing homes so one side is for the family that runs the farm and the other side is where that couples remaining parents lived. There is a door separating the two sides so grandma can come over and watch the kids for a bit and have supper but can get away when she gets tired.
All that to tell you that its a big house originally intended for a bunch of people and all with one bathroom. Its actually sort of a second hallway connecting the two that can be locked on both sides kind of like a dorm bathroom between two suites.
There are a number of these homes around here, some with the one side even smaller because it was a servant/hired hands kind of situation but the same setup.
Im not sure why so many people today have such a hard time waiting their turn. If there is someone constantly on the toilet then maybe they need to rinse the soap off their dishes better or stop eating so much Mexican food.