Why it is ridiculous to say that a great hitter is more valuable than a great pitcher

As the season gets close to ending, the MVP talk is starting to heat up. With the awesome year Justin Verlander is having there has been some talk about whether he should not only win the Cy Young Award, but perhaps the MVP as well. Now I don't want to discuss whether he deserves it as not (I like having separate awards for position players and the pitchers, but that is just my little opinion), but there has been one interesting critique that I want to smash. Some have said that a pitcher can't be as valuable as a position player, because the position player is on the field everyday, while the pitcher is only on the field every 5 days (or on the Yankees and White Sox, 6 days). Before we look at some statistics, lets just reason this out. In a 5 day span a batter (in a good offense) would get about 20 plate appearances. In a start, most pitchers will face at least that many batters (not to mention, a pitcher can shut down the entire lineup for the entire game, ensuring a win, a hitter can only drive in a bunch of runs, which doesn't necessarily have the same value. For example, a hitter can get 5 rbis but the pitcher could give up 6 runs. If a pitcher shuts out the opposing team, they can't lose). As far as fielding, most defensive chances are routine plays that every major leaguers could make, with probably one sparkling opportunity (rough estimate) in 5 days (except Sam Fuld and Asdrubal Cabrera, who seemed to make 1 a game in the first half of this season). Not to mention that a great pitcher can be pitched around, if not pitched to. You can't "hit around" a pitcher (besides maybe bunting). But now to statistics (mainly Sabermetrics), we will look at 4 players: Cliff Lee, Curtis Granderson, Verlander, and Jacoby Ellsbury (all Cy Young and MVP candidates). Because most statistics between pitchers and hitters cannot really be compared (the only really other thing we have is comparative standards, like a .300 batting average is the standard of good, as is an ERA of under 4, etc. That wouldn't be helpful), we will have to rely almost exclusively on the statistic WAR (Wins after Replacement, which measures how many wins the player gives you over a regular player). For many people, Curtis Granderson is a favorite for the AL MVP, and his WAR is 5.2 (its actually negative on defense, meaning he is an under-average fielder for the first time since he became a full time player in the big leagues. Verlander's WAR is a shocking 7.7. Ellsbury's is 6.5, making him more valuable than Granderson, but still not as valuable as Verlander (all this is according to how Baseball Reference, one of the most respected places for baseball stats rates the WAR). Cliff Lee has thrown himself in the ring as well, with a 6.1. Unless one believes that WAR (and sabermetrics in general) is just bogus, then it appears that great pitchers are at least as valuable as great hitters.