In answer to Yourself's question about where the Empire vs. King narrative occurred in history:
Other than the resentment that a few monarchs had towards the Byzantine Empire, there is no real Emperor vs. King conflict in the medieval period, because, again, the Holy Roman Empire does not count. Fantasy games are simply re-appropriating a narrative constructed in a later era and imposing it on a medieval setting. The Empire vs. King archetype came from the American Revolution where a democratic group opposed a mad controller of an exploitative empire. All fantasy stories have to be set in the middle ages because that is when Lord of the Rings took place, so in order to use this narrative that is instilled into the American character, fantasy games always portray the king/queen/prince/princess/frog-princess as being a monarch of the people, thereby making them seem like they are "democratic" and sympathetic. No medieval monarch was ever like that, because they were not raised to think that their peasants were worthy of rights or food for that matter. Fantasy stories stretch the truth in order to make it applicable to a modern audience who were raised to love when Democratic underdogs take on an evil empire.
Yourself might claim that this narrative is boring and black and white, but there is a lot of evidence which suggests that this narrative is loved and valued by Americans:
1. America's decision to join World War I. There was no real difference between Emperor Wilhelm II and any other monarchs, but we convinced ourselves that the German Empire was evil, so that we had the moral grounds to enter the war. We had an obligation to join the other pseudo-democratic powers, like England, to combat the "totalitarian" empire because of this narrative.
The Once and Future Jedi
This is not to say Yourself is wrong in his assessment of the genre. I can think of exactly zero video games who are able to take this narrative and apply it to a medieval fantasy setting successfully, and can think of about a billion that do it poorly (looking at you Fire Emblem!). To be fair to the industry, it is a bit difficult to make this story work in a medieval context, and difficult things are hard to do!