>double the rooms...for little tangible advantage.
I grew up in a mixed-class suburb, and many of my friends were the children of professionals (doctors, dentists, lawyers, businesspeople, etc.) with very large houses. So yes, I understand that some people think it’s important/useful to have a large house. None of them seemed to have a higher quality of life than my friends whose parents were professors, artists, teachers, etc. and lived in “normal-sized” 1000–1800 sq. ft. houses. In general, the large-house parents worked all the time, commuted longer distances, spent less time with their kids, and seemed generally less happy. On average the kids were probably also somewhat less happy. Having a big house, and having fancier material possessions more generally, isn’t really the most useful priority for most people to meet their primary life goals, in my opinion. YMMV.
At a world-wide scale, if every family needs to have a 3000+ square foot mansion on a separate lot, we’ll stay on track to wreck the planet.
The price of a two bedroom apartment in SF will get you a 3,000 sq ft house with a quarter acre of land elsewhere.