(The following is an editorial on the .400 average):
My father and I used to discuss the elusive goal of batting .400 (both of us are baseball fans, but not rabidly so). We came to the likely conclusion that the demise of the .400 average is largely due to a concept we take for granted today: Relief pitching.
Baseball has scaled well in talent since the turn of the century. The scores have been about the same... the averages have been about the same... the players have been a good match for each other (for the most part). Training has gotten more intense for both pitching and batting. Both of their arts have improved and matured technically until they have reached where they are today. Why has relief pitching helped so much? Because in no place in baseball do you see an area where stamina is so important (and having a large bench on your team so beneficial) than in pitching.
It is easy to notice that pitching takes more long term effort than batting (and other positions in fielding). Rarely these days do you see a person who pitches nine innings and lives to tell the tale (if you will). Many times you will see people who get put in for only one batter or two. There are usually two types of pitchers: starters and closers. Roughly, the starters have the power and the endurance, while the closers have the short burst of fire to retire the sides.
Back then, a fairly fresh batter could destroy the pitches of a very tired hucker in the eight inning. Slow pitches to the strike zone make for an easy target for the home run hungry. We immortalize those baseball greats that weren't athletes (look at Babe Ruth), but rather heroes. Those who made the hit in the pinch... the everyday man who could pick up his plank and destroy a ball in the bottom of the ninth...That is what made those players legends, not the stats.
Those are the Hall-of-Famers in the .400 list: the CrackerJack boys; the baseball cards with a stick of gum idols. Those were the days before pitches were marked with speed guns, before there was stats on what they do while they are in the bullpen. These people played in a time when baseball was a game, and not a sport.
In response to OJ, this also happened to Ted Williams, the last of the 400-club:
The intentional walk: As my grandmother often recalls, Ted would step right over and swing at them. Since he was so likely to get a hit (hitting over .400 by any measure is excellent), oftentimes in a pinch, pitchers and coaches would call for the intentional walk. While not particularly fair (but massively strategic), this tactic slowly hurt Williams' average.