What are some of the most common misconceptions about political corruption?
One of the most enduring misconceptions about political corruption, at least when it comes to those countries that suffer the brunt of it, is that it's akin to a disease that prevents the body politic from properly functioning. Even the name ‘corruption' itself denotes an abnormal functioning of a system, as if corruption viruses and nepotism bacteria infiltrate the state's bureaucracies and infects its administrators and lawmakers, forcing them to act irrationally, against the common good.
While this metaphor does have its use as a political selling point ("Stamp out corruption", "Eradicating corruption", "Drain the swamp!") it fails to point to a solution to the problem since it implies that there is a ‘cure', a ‘treatment' or some sort of ‘medication' that could ‘heal' the system and allow it to properly function.
More often than not, rather than being ‘corrupted' by webs of nepotism and rent-seeking actors the system is defined by them. Patron-client relationships are the bones of the system while favours are its lifeblood, with the common good being a thin skin that confers a veneer legitimacy to said system.
As such, any effort to tackle corruption that only address the outward signs such as high profile cases while ignoring the culture that allows such cases to appear in the first place will only bring half-hearted results. Convicting a few high profile offenders is easy, changing a society so that people stop thinking of the common good in zero-sum terms is much, much harder, requiring a long term strategy that bears little fruit at first. In the age of "learn a language in 2 weeks", few people seem to have the appetite for such an endeavour.
 i.e. the developing world but not exclusively.