We invented it, so why do we claim victory?

baseball, American football and basketball are all
American "inventions" - so why do leagues claim their
winners to be World Champions? It's a domestic (or at
best two country - with a couple of token Canadian
teams) competition!

sure it's most likely the reigning "World Champions"
would beat any other in the world - but who wouldn't
at a game you made up?
 -Wireskin

Shaun:  That's a good question, I am going out on a limb here, but I think it makes us feel better about ourselves.  That and we like to see if the foreign countries can beat us at our own game! 

Greg sent us his answer:  

Aside from baseball, as far as I know it, Basketball and "North American Football" were invented in Canada. That could be why but I doubt it. And isn't it funny that in hockey, another Canadian invention, it's called the Stanley Cup not the world championships of hockey or something like that.

MPM sent us this updated answer: 

Basketball was invented in Springfield, Massachusetts. The inventor *moved* from Canada to the US before creating the game.

The NBA is the world's strongest league bar none. Any team that wins the championship would cream teams from any other league. Exhibit A, 1992 Olympics.