
The average is higher but so is the median. A lot of the densely packed slums in US cities were physically destroyed which got rid of a lot of the homes that had very very small space per person, and newly built homes in the ever expanding suburbs after the roads were built out take up much more land and space is at less of a premium than in the cities where the land was very expensive and required building up and new construction standards were significantly higher than they had been.
On the good side this meant that families with a home had more space to spread out in, on the downside the destruction of the slums made it much more expensive to live in the cities with everyone competing for the remaining bigger homes and brought down the urban core populations (Manhattan is still down ~700000 prople from the peak of its population in the early 1900s) and the physically spreading out into the suburbs requires much morr inefficient infrastructure, more environmental impact, etc. Urban people who may have in olden times still been housed in cheap tenement slums now go without and are homeless because there’s a cliff between the streets and the most affordable housing whereas the slums used to make it a more gradual slope.

I had some annoyances with this. My old company had a requirement to do some annoying tasks in intervals that depended on the inverse of the number of tons of fuel used and the document controlling those tasks said just that: ‘tons’. But if you looked in the documentation behind that requirement, it was made back when we’d been involved with a European company for sourcing that fuel so that requirement was actually based on the inverse of specifically the metric tons of fuel used, not short tons. So all the math on determining the interval for doing that task had to involve converting for the metric tons of fuel used in the interval even though the newer fuel supplier we had swapped to and we ourselves were using short tons in essentially every other context. And since the controlling surface level document just said ‘tons’ without specifying which kind I was always having to correct the math of schedulers and new people on my team since they would eternally think we had more time to perform the task than we actually did and respectively plunk it down late or tell someone who was asking that it be moved that it could be pushed later than it should have been.