Miguel Cabrera is proving me wrong. I had done extensive research and concluded that a batter leading his league/conference in home runs (HR), runs batted in (RBI) and batting average (BA) in the same season had become almost impossible in large part because of expansion since 1961. In other words, there are just too many other players: twice as many in the National and about 80% more in the American than in 1960.
Miguel Cabrera of the Detroit Tigers is tied in HR with Josh Hamilton of Texas at 42. That is where Cabrera is most vulnerable. Cabrera leads Mike Trout and Joe Mauer in BA .331 to .323 and Cabrera leads Hamilton by ten RBI.
I'll post my research again soon.