Winning the World Series MVP requires a tremendous deal of luck. You can be the best player in the multiverse, capable of hitting .800 or striking out 40 hitters in a single World Series, but if your team doesn’t make it that far you stand literally no chance of winning the award. Team success is a huge prerequisite, and then all it takes is one phenomenal week and poof, you trick generations of people into thinking you were one of the best players in baseball history.
Sure, there are some historically great players who were world beaters in the regular season as well as on the biggest stage.