Generally sports that are about controlling the ball (or puck) will be more about superstars and less about teams relative to other games. At any given time one

Generally sports that are about controlling the ball (or puck) will be more about superstars and less about teams relative to other games. At any given time one person has the ball and that person has an outsized effect on the play in that moment. If one player is significantly better than the rest of the team, you can make sure they're the one doing most of the playing. With baseball the pitcher of course plays a similar role, they have a major outsized effect since they are involved in every single defensive play, and in a critical way. But they can't physically play very much. And then on offense the best you can do is put your best folks at the start of the lineup so they get an extra at-bat over the course of a game. (Of course none of this justifies the claim that only in baseball does team-fandom make sense; fandom isn't a logical construct to begin with and doesn't need some logical reason to exist.)