I think most people don’t consider your Hollywood examples as very cultural because it’s “pop” culture, and adheres to everyone so it’s kind of like cheating. It would be like saying “candy” is unique to your culture, every culture has candy, it being in your culture does not make it especially significant. When I think of American culture I think mostly of a subset of counter cultures, but mainstream cultures would be things like: house parties, cheap beer, california wine, football parties with greasy food, proms, protests, self-help books, fast casual restaurants, outrageous advertisements, and with the regards to movies I would think the way a movie gets produced in America and legacy of the studios is far more uniquely American than the actual stories they tell.