More games are played b/c baseball is less demanding than other sports. I'm sure that if it was feasible the other sports would too. The beauty of playing more games is that it allows the cream to rise to the top with more certainty. More games played = bigger sample size to show who the best is. Then, if we're more certain who the best teams are, only let them in. Plus, like I said earlier, baseball is more open to variance (another reason to play more games), so worse teams have a much better shot of winning a series unlike other sports. Therefore, we should only let the most deserving teams in.