Power and magic. And I don't mean physical power

Recently on The Big Purple, I encountered a pure example of the Argumentum ad Fireballum fallacy, so pure it actually spurred me to write this post.

In a discussion about the PCs gaining power in a fantasy world, we were trying to explain that PCs should be doing some specific kinds of stuff if the player wants them to gain political power (and no, killing monsters isn't good enough, not if your goal is to become a king).

Then someone (name withheld to protect the guilty) uttered the following question:

"Which is relevant to a world that has had an entirely different history and properties how, exactly?"

My answer was, as follows:
"The argumentum ad fireballum fallacy holds strong, I assume?
The ways power is acquired and exercised don't change just because monsters exist. In fact, monsters were believed to exist for most of humanity's history. And the ways of power are what they are exactly as a result of said history!"
Think about it, people. Our ancestors believed in magic. They knew faeries existed. They didn't doubt the power of faith, nor the power of devils and demons. What does it matter that they didn't actually exist? A basic lesson in policymaking is that people react not to what is, but to what they believe is!

And yet, they had developed intricate forms of government, and power was still acquired by political actions (even when they involved swords).
There were some people who put the beliefs of the time to the service of their political ambitions. But none of them managed anything without playing the political game.