I don't understand this argument. The automobile is much younger than the country. Cars became broadly used about a century ago, the 1910s-20s. How many U.S. cities do you imagine there are that were created after that? Or even that, due to cars, dramatically changed their size relative to the overall population?
Created, or built-up, expanded, and for more heavily populated? The US population has more than tripled in that same period, and the percentage of those people living in rural areas dropped precipitously.
