I think corruption is like a weed. It grows when you become acclimatized to your environment and start to exploit it.
Term limits get us closer to a part-sortition. From the wiki:
Author James Wycliffe Headlam explains that the Athenian Council (500 administrators randomly selected), would commit occasional mistakes such as levying taxes that were too high. Additionally, from time to time, some in the Council would improperly make small quantities of money from their civic positions. However, "systematic oppression and organized fraud were impossible". These Greeks recognized that sortition broke up factions, diluted power, and gave positions to such a large number of disparate people that they would all keep an eye on each other making collusion fairly rare.