and why should it be the richest? anything special about it being "American"?

i would wager the the stats aren't the full truth. it lists german middle class below, which is hilarious - income alone doesn't mean shit in countries with top notch public infrastructure and well organised health care. that US middle class family needs to pay health insurance on top, if their kids want to go to college an ever increasing tuition, pretty likely need multiple cars to get anywhere and have less vacation time.

if more US citizens would travel their view on how much they're getting ripped off would change drastically. US immigrants from india, china, africa still get an improvement, but for northern Europeans, incl the Swiss, Austrians, moving here is a step down in a lot of factors.

"world's richest" - haha.