There are plenty of huge burgers to be found in the US, but it's an overgeneralization to say that that's the norm. I view it as more of a he-man fascination: a fad among the same people who like to have a raw egg on top of everything they eat.

Here's an excellent photo essay of how burgers are traditionally done in my part of the Midwest: The Smashed Crispy Burgers of Central Illinois.