That's not to say we don't need full time sheepdogs, we obviously do, especially for defense against the wolves and bears out there. However for the other less dangerous but still very numerous predators, there will never be enough full time sheepdogs, the flock needs there own teeth for those.
Think of us more like elephants. Peaceful and productive members of the herd to be sure, but ready to stomp threats, without having to wait for the sheepdogs.
Dang fingers have minds of their own.