Right-sizing
Centralisation breeds corruption. This is because centralising any resource makes it economically exploitable. People don’t do corrupt things because they want to be evil, they do them for personal gain.
It’s a cost benefit thing, in which severe consequences are seen as acceptable risk because they are unlikely.
Organisation that is larger than a single culture is especially susceptible to corruption because the bulk of contributors to a resource pool fall outside of the subculture that manages it, and it has always been acceptable within a culture to mistreat outsiders provided only that this should not threaten the wellbeing of the entire subculture.
This is why there is a don’t-get-caught mentality. Members of a ruling subculture merely look the other way. Should one of them get caught they all feign outrage and disapproval. This focuses plebeian disapproval on the individual’s actions and away from the culture in which this type of corruption is rife. When the dust settles such subcultures generally look after their fallen; they must, or victims might not cooperate in diverting attention away from the fact that the ruling culture is wholly corrupt.
The only way to stop this from happening is to ensure that it remains uneconomic. This is not so hard; the ostensible purpose of centralisation is to obtain economies of scale, and these do not continue indefinitely: past a certain size the economies of scale are often negative. Find the sweet spot, and stay in it.
Power generation is a good example. Power stations just large enough to run a neighbourhood are cheap to build and maintain. You can shut them down for maintenance without losing power by shunting the load onto neighbouring grids, and you don’t need a massive distribution grid. The parts are small enough to transport easily, and so many of them are needed that they become commodity items, causing the cost to plummet.
So why does our society so love big and central? It is, or rather, it appears to be, easier to tightly control. Our leaders love telling us what to do. That is why they gravitated to the business of government, and it is also why anyone who wants to govern is profoundly unsuitable for a leadership role.