Most of the guys who are like that are actually macho, elitist, stuck-up jerks.
Not all of them, of course, but by and large they have to act like that to maintain their status in their social circles with their high-powered career peers.
Imho, it's more a result of the cultures at the schools they go to than anything else.
I saw perfectly nice people turn into stuck-up jerks after transferring to the high-powered prep school in the area.
I saw others, who refused to conform to that, become ostracized at that school.
American guys run the specturm, though, just like everywhere else.
My teeth aren't anywhere near perfect, I went to a small school with an alternative education program (and I never graduated), I don't have a high powered career, and my massive car is well over a decade old and in need of repair.
I dunno about my personality, I'm usually pretty nice but have, at times, been described as 'prickly'.
That's just me though.
What's a typical American guy like?
Might as well ask what a typical aspie is like.
The answer would be just as meaningless.
Certainly not what they're portrayed on the screen as, though.