Regardless of which group of politicians is in charge we will always see corruption if we leave the solution in their hands. . They will never take the steps necessary to eradicate it for the reasons you mention. This leaves it in the hands of civil society and the power of money. Money in the hands of individual investors, the business sector, the numerous fund managers and the broader financial sector. This power of money needs to be wielded far more effectively. Futuregrowth have already demonstrated how it can be done to devastating effect. So has the IDC. We need MUCH more of this. 

We must start with individual investors who must monitor how their money is being invested and aggressively tell their fund managers and their bankers how to behave. If they fail to do so then withdraw your support. Make it clear that if they invest unwisely in corrupt state, provincial and city structures that you will hold the directors liable. Pile on the pressure and start NOW