Baseball playoffs may or may not be luck-based, but compared to other sports there is no other factor I can think of that is similar to the effect of the starting rotation. In football the quarterback has a similar game-changing effect as a starting pitcher, but a team doesn't have a different QB in different games through the post-season. (In all this, I'm excluding the effect of injuries, which affects any sport.) Hockey has their rotations throughout the game, but over the course of the game the coach has the best players in for the maximum amount of time, and the best goalie plays every game. In basketball I don't think there is a position as determinative as starting pitcher or QB. Baseball managers would prefer to have their best pitchers available for key games, but sometimes fortune intervenes and that pitcher was needed in order to assure a playoff spot at all. And in the WC, if you use your best pitcher then he's not available for maximum duty in the next round. It's not luck, exactly, but if by chance your ace isn't available for the WC, and you win anyway, then you are better situated than if otherwise. It's "luck of the draw", in some ways, except it's not a random draw, it's the way the pennant chases unfolded, for instance if your division happened to be more competitive than others. I think the overall issue of Starting Pitcher has a lot to do with the "crapshoot" nature of how some view baseball playoffs.