Well, there are triple crown winners who missed the MVP. Trout has had a season like Mays. The triple crown was more important when there was less video of defense so objective voters could not factor it into a player's value. Also, the RBI stat used to be credited too much to the hitter.
Here's another way to think about it. I'll concede you AVG over OBP and I'll even let you factor is RBI not adjusted for opportunity (like % of runners on base driven in). I'll even say you don't have to do HR on rate basis because this is a season award (rates will help Trout on HR and RBI). Just count the 5 traditional measure of stats that are typically considered in 5 by 5 fantasy - AVG - HR - RBI - R - SB. Runs are no less valid than RBI measuring a players performance. An SB is directly useful only if it leads to a run, but SB are a nice proxy for speed which helps in lots of other aspects of the game and an SB threat helps other hitters, too.