America wasn't devastated by WWII. Our pre-war car infrastructure wasn't destroyed, and post-war prosperity meant that it was more economical than it might have been, in the short term, to put every American family into a car. Countries with populations temporarily too poor to afford vehicles, and gas, and roads, and pump stations, and gas lines, and so on, would have been more likely to build mass transit. Once wealth returned, American consultation (and aspiration to our relatively more affluent lifestyles) would have come into play.

It's a rare case where American Exceptionalism is a fact.