Let's say the concept of monarchy was never used in the history of mankind. How different would the world be? How many wars would've been avoided, or fough?. What empires would've crumbled? and which would've risen (In this scenario, any major nations or empire that could not exist without a monarchy in place, we are gonna imagine they follow standard democracy, as not to change history too much)
They say that some of the first societies didn't have leadership castes. Realistically, any group of people with resources are going to be attacked by people who want those resources. This would then lead to needing a war leader anyway. I'm not sure that it would ever be possible to have a big civilization that lasts very long without clear leadership. Now, how do you keep that leader from setting his son up as the next leader? That I can't say. Maybe somebody else has an idea.
Too ill-defined. The things that made monarchies arise are inherent in societies. You need to redefine what characteristics of human nature are different for this to happen.