Bill James looks at the history of teams that could not turn regular season success into post-season success. One of the more interesting bits comes in Section V, where most of the long-term success in both regular and post-season play is concentrated in six teams.

I am printing the chart, really, so that you can see where “your” team ranks on the chart.  The Yankees over a long period of time have enjoyed almost twice as much success per season as any other team, which is not surprising.  But this is surprising, to me.   The average level of success for all teams, per season, is 20.5 LBS points.  But only six teams—three in each league—meet that standard.   The only teams that have an “average” level of success, over time, are the Yankees, Red Sox and A’s in the American League, and the Dodgers, Giants and Cardinals in the National League.  All other teams, over time, have been below average.

BillJamesOnline.com

According to this method, the Diamondbacks and Rays are the most successful expansion franchises, and I have to believe a smaller sample size and an easier path to a division title had something to do with that.