And who calls something 'the world series' when only Americans play the damn thing. When other sports have a 'world tournament/cup' countries play other countries, that's how that works. 😛
American and Canadian sports refer to their championships as "world championships" because every other league in the world acts as a feeder league to the NHL, NBA, NFL, and MLB.
It would be nonsensical for the best team in MLB to play a team from Japan or Mexico because all the best players from Nippon Pro Baseball and the Mexican League get drafted or signed by MLB teams at the end of every season.
The worst team in Major League Baseball would absolutely annihilate the best team in the second best league in the world, which is Nippon Pro Baseball.
The same goes for hockey. You could make an all-star team of the 25 best players on the planet outside the NHL, and the worst team in the NHL would crush them 99 times out of 100.
Contrast this with soccer, where the best players in the world are scattered between several teams in several different leagues. Some are in the Engilsh Premier League, some are in Bundesliga, some are in Serie A, some are in La Liga, etc.
Basically, with US/Canadian sports, there are 30 to 32 teams per league and the respective rosters of those leagues contain all the best players in those sports that are alive today. If you took every single soccer league in the world and picked the ~400 best players and made several all star teams out of them, that would be the soccer equivalent of what the NHL, NBA, NFL, and MLB are.