Corruption and fraud stem primarily from lack of controls which are a result of poor or non existent management skills.  The lack of bureaucratic and institutional capacity is a legacy of apartheid. The intelligence and intellect of civil service empolyees that should be focussed on applying basic management systems and  that are designed to prevent corruption and fraud, are instead being applied, unhindered, to criminal activates.
The DA has shown that it is possible to run parts of the country relatively cleanly by insisting on professional management, auditing etc.  Whether enough  capacity and skills exist in SA to enable the DA to roll out their government systems on a wide scale is unknown  but seems to be the only possible way that the country might be rescued.