https://www.fanniemae.com/media/45106/display
> The causes of the housing supply crisis are widely understood. After the Great Recession, new home construction dropped like a stone. Fewer new homes were built in the 10 years ended 2018 than in any decade since the 1960s. By 2019, a good estimate of the shortage of housing units for sale or rent was 3.8 million. The pandemic-induced materials and labor shortage exacerbated the trend, however, as evidenced by the surge in rents and home prices in 2021.
It is cheaper per square foot to build a larger house and many people like to live in big houses, so new construction has grown in footprint.
Many people value efficiency only when doing so is necessary for them to afford energy and maintenance costs.