well, back in the early 1900s it was called the "world" series as a marketing ploy, and it kinda stuck. personally, i refer to it as "the fall classic" an argument could also be made that a great number of nationalities are represented in the MLB, and they are the best players in the world. every baseball player with high goals eventually wants to play in the MLB, regardless of where they are from.
http://www.neboagency.com/...ent/uploads/Team-map1.jpg
and those are the countries that participate in the world series!