There have been 20 perfect games thrown in major league history (in nearly 400,000 games). Save for one botched call (don't even get me started ...), baseball would have witnessed three perfect games in the past 24 days.
The perfect game is supposed to be sacred. Vin Scully's call of the ninth inning Sandy Koufax's perfect game in 1965 is regarded as the best of his career (listen here). The three pages in Stephen Jay Gould's "Triumph and Tragedy in Mudville" on Don Larson's perfect game in the 1956 World Series still make me tear up (read the whole thing here).
Why is pitching so dominant these days? At what point is this string of perfect games no longer a statistical fluke? I'm having trouble finding a comparison of batting averages and runs scored leaguewide by season, but these statistics would give us a clue as to whether pitchers are beginning to get the advantage. I can note, however, the dramatic drop in home runs the past few years, which has been attributed to the crackdown on steroids and other PEDs.
Gould's book has a wonderful discussion about how the rules of baseball have changed over the years to preserve the optimal leaguewide batting average of around .260. As training and strength regimens evolve, sometimes pitchers start to get an edge over hitters (or vice versa). Various rule changes have helped restore the historical success ratios, such as cork-centered balls, the "lively ball" era, and changes to the height of the mound and dimensions of the strike zone.
Gould argues, and I agree, that baseball should never let .400 batting averages or sub-1.00 ERAs become commonplace; instead, it should tweak the rules whenever the statistics get too far out of whack.