Is there class in America? Yes, and Mumford and Sons are convinced otherwise. That's because of the sheer scale of this country. British bands are routed through venues and sent packing; they rarely see much of the landscape or see the grinding poverty in towns that are not served by concert venues. If you wear tweed in America, people just think you are a professor of literature or something like that.
I don't understand the appeal of Mumford and Sons. I have given up trying to figure out why a band like that can succeed while others end up by the wayside. I certainly can't explain Radiohead to anyone; why there are legions of ravenous fans who eat up the crackly, moaning, broken glass dissonance is beyond me.