Jack, the circumstances drive the tactics. For instance, the famous gunfights of California watchmaker Lance Thomas found him in a relatively enclosed space with little option for tactical movement, yet he was still able to kill multiple armed robbers in a string of shootouts. A driver seat-belted behind the steering wheel when he has to engage a carjacker will have even less movement option (not counting those available through the accelerator and steering wheel).
Moving while shooting, and moving and THEN shooting, are both important skills to "have in the toolbox," but won't always be applicable in the given situation.
Often, the best potential for life-saving tactical movement occurs in the moments PRIOR to the gunfight, when the alert citizen has seen danger signals and maneuvered to create distance or get behind solid cover.