I was born in 1964 in the midwest US, the 7th out of 8 children. The house was a two story brick structure with five bedrooms and two bathrooms. The house was less than 2000 sq ft, but that included a moldy basement with seepage and jackposts all over the place helping support the sagging joists, so the real living space was closer to 2/3 of that, so 1350 sq ft or so.
The house had been built before 1920 when expectations were less grand; those rooms were much smaller than nearly any home I've been in built after 1980. When my grandpa came to visit each summer, it meant all five boys in one room, the two youngest in sleeping bags and occasionally getting stepped on in the middle of the night when one of my older brothers would get up and forget we were there.
There was also no air conditioning, nor ceiling fans. My parents had a box fan in their bedroom window during the summer. It was a big deal when the bedroom I shared with my next older brother got a box fan too; that was in high school.