American society does focus a great deal on the perfect body, but think about the face as well. I mean there's so much airbrushing done on these celebrities and models. They also use tons of make-up, even on men. Perfect skin and hair also plays a huge role on how Americans define beauty. Also think about how much money these products cost. It is such an effective advertising strategy. Wear this 20 dollar bottle foundation and you'll look like this movie star.
I think at least some of them are starting to make progress but this perception has been going on for decades so changing it will probably take twice as long