I'm not American but German and live in the beautiful cosmopolitcan city called Berlin.
I understand that the US has a lot of diversity. You have fat people who live in the Bible belt who don't believe in evolution.
On the other hand you also have things like Burning Man. You don't have to live in "mainstream culture".
Two decades ago an book review in a major mainstream publication made a book. The same isn't true anymore. Mainstream media is a lot weeker than it was two decades ago.
Today the person who can sell the most books is Oprah. Oprah doesn't represent a consensus position. Her relationship with her audience is a different one from the relationship that a New York Times book reviewer has with his audience.