Yes but it is South Africa and the ANC is still seen as the "liberation" party.  If there was a vote tomorrow, with Zuma as head, it would probably win with over 60%, even in townships where service delivery protests are taking place.
And one thing about African liberation movements is that the old guard have a sense of entitlement to power and rich living off the back of the state.  In places like Kenya that entitlement has been passed on to the kids.
So do not be surprised that when mother nature takes it course and Zuma is pushing up the proteas, another Zuma takes his place.