More than any other superhero, Batman is a reflection on America. He is the only masked marvel whose movies consistently earn tens of millions more in North America than in the rest of the world combined. (Sole exception since 1989: Batman and Robin. Maybe it was funny in Italian.) Action blockbusters typically make about twice as much overseas as domestically. Even Captain America (which was called The First Avenger in some territories) earned more overseas.
If Superman stands for the ungainly immigrant who came here after his people were wiped out in a holocaust and realized his full potential thanks to America, Batman represents the anti-collectivist. He captivates America for the same reason communism never caught on here, the same reason citizens hold firearms for self-defense instead of just hunting, the same reason we are the only country that questions the wisdom of socialized medicine. He is the avatar of a people whose primary wish is to be left alone.
Because they didn’t offer as much opportunity, freedom, and hospitality to immigrants, no European nation grew as large and strong as we did. Hence European countries generally aren’t powerful enough to fight wars on their own, necessitating tangled webs of alliances and a keen interest in what the neighbors might be thinking. The U.S. takes little interest in others’ politics and, protected by history’s two largest moats, can choose which wars to join, always as the senior partner or even alone if need be. The European Union constitution (aka the Treaty of Lisbon) is upholstered with guarantees about all the wonderful things the authorities can do for you in exchange for granting them more power; the U.S. Constitution bristles with warnings about what the government can’t do to you. Even the European press is much less antagonistic toward government than ours, which patrols the night restlessly in search of wrongdoing.