The Civil War (which was anything but) is replete with examples of squandered opportunities for overwhelming victory. From Manassas to Antietam to Gettysburg, the course of the war could have been drastically changed with more aggressive commanders.
While it is true there was much bickering between Bragg and his subordinates, much of it was due to Bragg's incomprable ability to snatch defeat from the jaws of victory. A favorite of Jefferson Davis, Bragg was, to put it kindly, less than competent and had earned the justifiable disdain of his troops.
Polk was better suited to his duties as a bishop than a general, but even he recognized Bragg's obvious shortcomings.
Rosecrans, like so many other commanders erred on the side of caution, being satisfied with being left in command of the field rather than routing an obviously defeated enemy. It was a scenario that would be repeated throughout the course of the war.