There is a land ruled by Alchemists who have used their craft and powers to cheat death itself.
Centuries ago they learned how to create artificial humans without conscious minds that were useful not only as biological robots that could do basic slave labor, but as new bodies that they could transfer their consciousness into as to avoid death. The Alchemists only gift new bodies to those they deem loyal.
The ruling alchemists have been in power ever since they made this breakthrough, and they’ve ignored the rest of the world. The rest of the world however isn’t privy to magic and has had to survive through innovation.
The immortals still think chariots are the height of military science, while the outside world is adapting quite well to black powder.
Given a ruling class that is immortal and has compliant slaves for labor, is it reasonable to believe that innovation would be ground to a halt?
Essentially this question is about how much can society be held up by leaders who just won’t leave, and can such leaders squander a massive set of advantages?