I will answer this, when you explain why you asked for my email, then you blocked my messages
He inspired followers by his speeches, lectures, and actions.
The system that is criticized for causing an income gap between the social classes is: Capitalism
Capitalism encouraged people to compete with one another in the pursuit of economic resources. Since the wealth that acquired by the initial winner of the competition is transferred to their children, their children born with massive advantage over those who do not possess many resources, and caused the enlarging of income gap between social classes.
It spread more because more people had believed and it was past down through generations faster than Islam was. if this dosent help then u can ask someone else. :) :)