Maybe it's just me getting older but it seems like this has always been true across cultures and history. People like to believe that once they get power, they will act differently than the ones who came before. But in the overwhelming majority of cases, they end up being just like the people they replaced, if not worse.
Every once in a while you get an exception but that's why we remember those people - because they were the exception.
This greatly underestimates the level of vanity. Look only at the number of people who inherited their wealth, or received substantial financial support, yet still consider themselves self-made. I would also expect this to concentrate deistic thinking as people with a religious mindset will see being chosen as God's will and use the gained power to reinforce that.
I don't think I'd want to live in a country governed by the Dunning-Kruger effect. (Or maybe I already do?)