I agree with you wholeheartedly. I think certain elements within the camp simply could not stomach being led by Amla, and I think it could be our Broad&Jimmy equivalent a mirror of the KP saga. At the same time I think the captaincy carrot had to be dangled before certan individuals to make them change their minds.
Amla did two things which no other captain would have ever done - 1.remove himself from slips after a few dropped catches, 2.move back to #3 to give Faf several undeserved lives. Kallis would never have moved to 3 recently when Amla's batting was off form. He should have been dropped instead of batted lower. These two things alone - Amla bending over backwards - prove beyond doubt that it's not so much his humility but certain characters forcing him into such decisionmaking. What kind of captain can think properly chasing every 3rd ball to the boundary...especially in this case when England batted forever and plundered the South African attack??? That was humiliating for Amla and he had enough. They would never have dared suggest Smith move from slips. Even suggesting that to Amla undermined him.