I believe that the only sufficient condition for civilization is a genetic predisposition for intelligence and morality in the population. If this exists, then the various necessary conditions for civilization will fall into place. It is true that some of the necessary conditions may contribute to this sufficient condition, but this is not guaranteed. Only when this sufficient condition exists can one be sure that civilization will develop.
I admit that this is purely my hypothesis, just speculation. But I am just posting this to prompt discussion. What is your opinion on this question?