Hereditary monarchy gave England and the UK tyrants an tyrant-wannabes like Bloody Mary, James I, and Charles I, horn dogs like Henry VIII, Charles I and II and Edward VII, and the loony-tune George III. I'll bet ordinary English people loved living through The Wars of the Roses!
OTOH, in the past 30 years the US has had Horn-Dog Bill, America-Hater OhBummer!, and Brandon the Clue-Free.
The problem isn't with systems of gooberment, but with human beings. Any system can be exploited by bad human beings.