I think the answer is fairly simple.  A devastating  apartheid legacy was the complete lack of management education and training for Black people. The rapid replacement of trained Whites with uneducated Blacks resulted in a collapse of  effective bureaucracy on a grand scale. Good management routinely puts systems in place to limit fraud and corruption etc.  It sometimes fails eg KPMG, SAP etc but generally does not.  The incompetence of much of the civil service is not due to lack of intelligence but a lack of basic skills. Our disasterous presidency is the perfect example.