I think part of that is "Moneyball" has tended be more successful over the course of a 162 game season rather than the 5 or 7 game series of the playoffs where

I think part of that is "Moneyball" has tended be more successful over the course of a 162 game season rather than the 5 or 7 game series of the playoffs where there can be a lot more variation in outcomes. I also think the analytics quickly caught on across the league so the A's advantage was short lived. Now pretty much every team is very heavily invested in it.