This is the best part about baseball and why it's so difficult to win on a consistent basis. It has more randomness than any others. Of course a 7 game series is going to be more selective than a 3 game. It does create more suspense and interest in the games. As someone else pointed out, the NCAA tournament is one of the most watched "sports" because of the one and done. however, most of the time the best teams still make it thorough.