De-urbanization was spurred by housing shortages post-WW2 and federal policy seeking to stabilize the housing market. The FHA was created to insure home loans that met a long list of requirements[1], which had biases towards increasing consumption (including cars) and racial segregation. The marketing and growth of suburbia was then promoted by various business interests that would benefit from that increased consumption[2]. The new suburban lifestyle led to the rise of modern conservatism[3]. Most (~85% [3]) of the US lives in metropolitan areas, so rural lifestyles are not typical and it would be vastly less efficient if everyone lived there rather than in cities.

1: https://marketurbanism.com/2017/09/12/financing-suburbia-how...

2: https://www.washingtonpost.com/news/made-by-history/wp/2017/...

3: http://americanhistory.oxfordre.com/view/10.1093/acrefore/97...