Square footage per capita can be misleading because it goes up as an area moves from low density to medium density, but goes down as the same area moves to high density.
Square footage of land != square footage of real estate. A stack of apartments is high density, but each resident could enjoy more square footage than if they were crammed into a single family home with a ton of roommates.
Adam smith observed in his book that as people get more money they typically spend is on nicer housing.
I dont have sources, but the trend for larger houses was happening much earlier than the WfH trend.
It's a mix of car culture, proprty value being lower farther away from cities so develops can create a high margin on building neighborhoods marketed on big, new houses.
I feel like McMansions peaked in the sub-prime era and that construction since has been smaller and simpler structures.
Could that also be explained perhaps by the fact that people are willing to live farther away from cities (where land / homes are cheaper and larger) because they only have to work 3 days a week from the office? Or because commuting is less painful with newer cars?