Everybody talks about the randomness of baseball in small sample sizes. Well, the playoffs are a small sample size. To top it off, all the teams in the playoffs are good teams, proven over a huge sample size of a 162 game regular season.
The best team doesn't always win in the playoffs, and you need to be more than just good to win, you also need some good fortune as well.
The most important thing is to bulld a team that is good enough to make the playoffs multiple times in a 5 to 10 year period, and eventually you should break through and win it all because at some point luck will break your way.