Evolution is a necessity. In muggle sports, they have often evolved to make them safer for the participants, especially after they found that repeated head trauma caused significant long term damage. The States is also incredibly different culturally, so it only makes sense they would adapt a sport to their more vigorous culture.
I was actually pondering the other night why quidditch brooms don't have some sort of integrated saddle that makes them easier to control with your knees. That would certainly change the game.