I entirely disagree there. Seattle is culturally different from LA and LA is culturally different from San Francisco, and none of them are really culturally the same as Portland, Oregon, and that's just the West Coast.
Heck, if you go to Texas, Austin is culturally different from, say, Houston.
I've lived in the Southwest, the Northeast, and the Northwest. I can say these areas are culturally different and if you don't see it, you haven't lived in enough places.
I think the big problem is that culture is largely invisible to those who grow up in it. All the little things you do, how you greet people, the little micro-dialects of the language, etc. are so second-nature that they are hard to see.
Heck, if you go to Texas, Austin is culturally different from, say, Houston.
I've lived in the Southwest, the Northeast, and the Northwest. I can say these areas are culturally different and if you don't see it, you haven't lived in enough places.
I think the big problem is that culture is largely invisible to those who grow up in it. All the little things you do, how you greet people, the little micro-dialects of the language, etc. are so second-nature that they are hard to see.