I think the MVP voting, like most regular season awards voting, takes place before the postseason starts. So postseason success (or lack thereof) wouldn't come into play. 

I think people see a Rockies player win the batting title and they don't even care anymore. Rockies have won it so many times that it's become devalued, unless a non-Rockies player wins it. Charlie has a good case for MVP but I think he's a long shot.