Why did Mickey Arthur quit as Proteas coach?

Question

A press conference is due to be held at 9am in East London on Wednesday 27 January, according to Cricket South Africa. But before Mickey Arthur and CEO Gerald Majola address the media there, there have been reports of a rift between captain Graeme Smith and Arthur but that just seems to be conjecture at present. Another theory is Arthur finally fell victim to his side’s failure to perform to expectations in recent times. All will be revealed in due course.