'Cos they're not the best at it. They only play sports that none, or few non-American countries play, this is why they have the 'World series' with no Non-American teams
If there was enough interst and dollars to be made. Someone in New York like George Stienbreener would buy the best players in the world and we would have the best team. At least for a season or as long as the pissing contest lasted. If it was important to have the best team.
I guess America says we need to let Europe lead and be good at something.
Teams in America are not made up of locals anyway. I wish they were but there not. You know they say wish in one hand crap in the other and see which one fills up first.