Justin Wolfers writes:
the real puzzle from the 2008 Olympics is why the United States is so terrible at transforming raw talent — the millions of Americans born every year — into world champion material. Moreover, the puzzle deepens once one accounts for the fact that, living in one of the world’s richest nations, U.S. athletes have unparalleled access to the latest training technology.
Um, what puzzle? If you’re an American boy who can run, you join the track and field team only after failing football tryouts; if nothing else, track and field has a much lower chance of winning you a college scholarship.
Additionally, the U.S. has a thriving (and very commercially successful) alternative sports scene. So living in the world’s richest nation, U.S. athletes (aided by skilled business managers, of course) can create their own sports, complete with related film and video game industries (just look at Tony Hawk).
In short, the incentives in the U.S. are aligned in such a way that Olympic sports simply don’t attract a lot of interest from potential competitors; better opportunities are available elsewhere.