Yes, you're right (and I had sort of forgotten), rooms with three or four beds do exist... at the bottom end of the market. I remember sharing a room with the whole family a couple of times as a child (once in Italy, once in Germany), though I recall that the rooms/hotels weren't all that nice. My aunt and uncle, with their five children, used to stay at youth hostels - i.e., hostels affiliated to national youth hostels associations for which you need a membership card.