If you are faced with multiple attackers, start with the highest threat based on, proximity, weapon, aggression, ect. A bandit at 10 feet with a shotgun is more of a threat than the one at 3 feet with a club. Put one into each bandit based on threat, return to those that need more.
Why do most criminals follow that path? Mostly because they lack the drive and motivation to pursue a career in anything else. Crimes are committed based on the motivation level of the criminal, the opportunity. Very few criminals are motivated or loyal enough to stick around when their cohorts start dropping. That being said, it is why they hunt in packs and descend on the victim in packs.
While not all inclusive by any means I think the NRA's Armed Citizen is the only data base at all that tracks civilian defensive use.
My rifle and pistol are tools, I am the weapon.