Why South Africans Can't?

its bad luck nothing else. they require some pure winner player like MSD and youraj singh.

Santhosh jee...

Like MSD and Yuvaraj they have many like Grayam Smith , Jaqus Kallis , Jean Paul Dumini now.Previously Gari Kirstan , Allen Donald , Jondy Rods etc also.But in all ICC Championships they get expelled.Is there any psychological problems to South African Cricketers when playing in ICC Tournaments?

They are not making it on the top edge. There are many players who are match winners but need to work more to reach the small edge they are missing every time.