There is no doubt that living in California means that I live in a cultural bubble. But I have the advantage of knowing what the outside is like, having grown up in rural North Carolina.
What is it like to live in the United States outside of rich urban areas? I offer two points to illustrate. First, a vignette.
In high school I worked at a grocery store. When I gave notice to my boss that I was going to quit my job to go to college, he asked me what I planned to study. I said "Physics". He asked me "what does Physics mean?"
If that sounds like a perfectly normal question to you then you are not from California.
Secondly, I offer an observation. I am shocked at the amount that people travel in California. It's unusual to meet a 25 year old that hasn't been to at least 2 or 3 countries. And some have been to 10+! International travel isn't just considered leisure out here, it's considered a vital part of growing up and living a well-rounded life. When I tell people that I haven't left the United States, they look at me with pity as if I told them that I had some terminal illness.
People just don't have the money to travel in other parts of the country. Californians are really rich. In some ways their lives are similar to other Americans, but they eat better food, they have fancier phones, and they travel an infinite percent more. Those things are all viewed as an extravagant luxury in other parts of the country.
People under-appreciate how big of a class divide is caused by geography. I'm optimistic that the internet will close the gap. But the differences are really big.