Interesting analysis but the key is game balance. A weapon may be more effiecient but less useful. The shotgun style weapons are super efficient but limited to short range, the sniper rifle is really powerful and accurate but takes a full turn for every shot. Looking at the numbers is looking at only a small part of the picture.
I will agree that pistols are pretty much useless at the moment and I don't even bother equipping them.
Edit: My mistake, just reread and noticed this was a realism debate as opposed to game balance debate.