IMO corruption is just a symptom. Everything goes back to one source point: lack of well-educated citizens who can push back without hesitation. Note that the two conditions: well-educated and can push back without hesitation. Missing any of them and the foundation cracks.

Also I wouldn't bother comparing corruption between democracies and authoritarians. I have lived under both and the only thing I see is the common human nature represented in different ways. And I see "lack of well-educated citizens who can push back without hesitation" everywhere.

I guess that's why we are in a world that keeps competing for incompetence.