All I can say is
most Americans are lazy. Either that or they have more business matter in hand.
As for Korean... They got nothing to do with their free time so they create games. Easy and simple.
Oh yea... Don't expect Americans to be good and do everthing such as business,war,technology, etc... Japan is more specialize in technology(robots

), China as population, American(good government?), korean is probably nuclear bombs(just kidding) and such... So each country has something they are known for. Don't expect Americans to be good at everything.