So called strongman leaders fear being unseated because they know if they were they aren't likely to live that long as they know those they have oppressed are likely to seek revenge.
Internally they retain control by a strong Police/military force that are kept loyal by either fear or being treated or paid better than the population who maybe starving and externally via a large and well equipped military and a nuclear deterrent.
This is why the world can only do so much against Russia and China, we might despise the way they treat those that oppose their strongman leaders but a full on conventional military confrontation is never going to be on the cards as both would use nukes if they believed their leadership was under threat, irrespective of the effect on their own people who they don't care about but they talk up the rest of the world being an enemy so they can justify what they do by claiming that even in the face of complete annihilation of the populace the people will have secured some sort of posthumous victory over the 'enemy'.
