if you think you can just plop a gun in a bag and bang off a good group like you describe above you have obviously never tried to shoot an accurate group at all before. I mean really shoot an accurate group. Yeah, it might be more accurate than just banging away in the same manner freestyle but it will be far from a "decent" group. It will be as poor of a rested group as the cramming the finger in the trigger standing will be to a freestyle group. To shoot a good group you have to work at it, its not easy. With a good grip and good trigger control i can still shoot a bad group off the bag.
good groups consist of three elements, sight alignment, trigger squeeze, and follow through. Other factors such as stance, grip, and finger placement only help in keeping ones performance from shot to shot more consistent, or aid in rapid follow up shots. I have shot my pistol with a bic pen pressing the trigger with great success. I've also held my pistol under the arms of a buddy(from behind so i cannot see the sights) having him sight the pistol and a third buddy depress the trigger. Again, with great success. The criteria required to produce a good group are simple. Maintaining consistent form throughout is what takes practice. Add in some dynamic movement and stress and now you're working for it. Shooting groups at a stationary target with no time limit is boring and easy.
that's correct and the best way to do this is breaking things down into smaller parts. Benching the gun is just a good way to work on trigger/sights.
No, it's clearly not the only thing you should be doing but it is something you should try....of course it's easier to sit in your chair and argue about it than it is to go out and try it. If you spent half the time you spent on this thread just to go out and try a few shots off the bag you might actually have something to add to this thread, good or bad.
again, where have i ever indicated that i have not shot a handgun from a rest? I have done so, many times. There's no doubt a rested firearm provides a more stable platform and thus improves performance, especially at distance. Focusing on trigger squeeze while observing proper sight alignment is less than constructive when done from non standard positions such as prone/supported. The vast majority of handgun shooting is done off hand. You don't need to see proper sight alignment to execute proper trigger control. Both factors must be present(along with your desired sight picture) to make hits, but the three factors need not be present to practice any one.
Shooting from the bag will as i mentioned before, eliminate the human error factor, which is what you're trying to observe and correct. Prone/supported shooting is the easiest and most accurate because it eliminates/mitigates the human error factor. Which makes diagnosing errors from a prone/supported position next to useless.
and yet pretty much every time you learn rifle shooting they start you prone...why is that?
In the military they always started us shooting prone before we moved on to other positions.
There is less influence from the shooter but far from none. You have to learn the basics before you can move on.
rifles are better suited to long range shooting which involves a higher level of consistency on the shooters part to make hits. Firing from the most stable(read least human error induced) position only makes sense. A handgun is not designed for long range. A handgun is an immediate access firearm for close quarters engagement. Short of getting caught in bed, there's few instances where prone pistol shooting is the norm.