Their are 17 countries with baseball teams in the world. The world series is just the MLB becuase the MLB is the most competitive league in the world. The MLB welcomes the top prospects from all over the world to compete for the ultimate goal of winning the world series.
Most countries have a national baseball team, as the game recently became an official Olympic event. "World Series" doesn't denote "worldwide" as Major League Baseball only spans the Western Hemisphere.