We've lived in towns big and small, in FL, GA, CA, and NC. We have families all over the US. Relatives who are millionaires and relatives who live in trailer parks.
It goes w/o saying that our respective families have very different ideas of the American experience.
Besides our differing families, because this is a country of immigrants, every place I visit in the U.S. is a bit different. Even within NC we can't even agree on a single style of BBQ. At the state fair the other day, I had a Cuban egg-roll (the innards of a Cuban sandwich deep fried inside a Chinese egg-roll ... genius!)
I recently learned that literally within the Koreatown portion of L.A. has sprung up a Little Bangladesh. And you know what, those immigrants will only contribute to the great melting pot that is America.
So I'm really at a loss to describe a single American culture, much less one that is under threat from today's immigrants.
I'm reminded of this clip from Bridge of Spies:
https://www.youtube.com/watch?v=-qI3SngYvUg
That, that to me, is what unites us. Not some abstract ill-defined concept of "American Culture".