Maybe because I don't have specific experience of running through dungeons destroying invisible monsters with my bfg? (Yet.)

You raise an interesting point. At a guess, I imagine if you asked a big game hunter or combat soldier with experience tracking a target and firing weapons with the intent to kill, they would probably notice the disconnect. I wonder if Guitar Hero has limited fans among those who can actually play the guitar, for this reason as well?

I play guitar and Guitar Hero; I enjoy them both. It isn't the same thing of course, but on the harder difficulties it does involve some of the same fretting motions. I guess I don't understand why real guitarists are such snobs about games like this. No one would argue that they are equivalent....

Several of my friends that play guitar detest Guitar Hero. I think you have a point. For those who can't play the real thing, it's a fun game, but it doesn't capture the experience the same way.

Playing Guitar Hero has more in common with playing a game like Simon than it does with playing a real guitar. I'm not saying this is a bad thing, it's just a very different experience.

One reason might be that truly simulating real life would probably make the game quite boring. Think about the limitations:

1) Your character gets tired.

2) You can't jump too high.

3) You can't carry 25 guns including a bazooka, sniper rifle and grenade launcher.

4) Reloading would take a long time.

5) If you jump off a ledge you get hurt.

Etc...

I think people notice its off, but ignore it in favor of having a good time. Eventually, if you play a game long enough, you might forget what you noticed, but thats more a result of playing a lot.