I think most people would shoot all they had in the gun before realizing it was ineffective, and that includes cops. I think that moment when your gun goes dry and you have to go for a reload is the moment you would realize your shots were ineffective.
Most of us shoot on a target like this:
Perhaps one like this and learning to dis-articulate the limbs would be better, at least for very advanced training.
The thing is that the typical CCW holder really doesn't practice ( And cops only practice when they have to usually). He goes through the course enough to get his CCW and that's it. That entry level course does not include any movement, no cover, no concealment, no body action at all. And what happens? They go to the training they do have, which is to be flat footed and stupid. That and they have never fired under stress of any kind.