I think there's a little more to it than that.

Yes, there's the fact that American culture is very dominant in pop culture and we've exported our culture around the world. As the Rammstein song goes, "We're all living in America"

But there's also the fact that we're a melting pot and we've happily appropriated bits and pieces of culture from everywhere else and integrated them into our own, and the lines get murky about where those other cultures end our our own begins.

And there's not really one American culture, we're rugged cowboys, and we're Hollywood movie stars, we're fat assholes and we're health conscious hippies, we live in modern cities, suburban sprawl, rural farmland, mountains, forests, frozen hellscapes, wide open plains, deserts, we're gun nuts, and we're pacifist vegans, jocks and nerds, some of the richest people on earth, and homeless on the streets and everything in between, and every part of the country does things just a little differently, so it can be hard to pick out things that are truly emblematic of Americans as a whole.