You don’t think a wolfhound is expected to fight to the death? Or a pastoral flock guardian? You think Great Pyrenees breeders are peachy-keen and dandy if their flock guardian takes a powder because he gets concerned about his own skin? What about boar dogs? A hog dog that quits in the middle of a fight gets other dogs and the hunter killed, and you can most certainly bet that dog is going to get a quick bullet in the head if he manages to survive the fight after tucking tail and running.
You don’t think a lion hunting dog is bred to be a relentless killer once engaged?
What about protection dogs? Do you think that working doberman breeders breed dobies who, when they get smacked around a little, pack it up and go home? Any of the eastern European herding breeds (GSD, Malinois, etc), you think people spend fortunes and lives breeding dogs to chase and fight bad guys, but who give up when the going gets tough?