A driver for change (and control) is Religion and to varying lesser degrees, Quasi-religious thought.(Communism Fascism Capitalism etc.,)
At best they call to the better aspects of our humanity, at worst they are a vehicle for thought control.
We can see in our current milieu various groups motivated to extremes by their belief systems.
An interesting case is the transition of the militarist republic in Rome to the Roman Catholic Church. Rome was stretched militarily and financially and this pesky bunch of trouble makers (Christians) were gaining popularity. Despite persecution, they refused to go away. In fact it only seemed to encourage them.
Somewhere in the workings of the Imperium, someone made an interesting observation. These Christians were highly motivated and followed their leaders willingly. A much easier and cost effective way of controlling the population than military force.
So the Imperium converted to Christianity and the Roman Catholic Church was formed. It effectively contracted out military and judicial control to the Feudal Lords, but demanded allegiance and tribute, and largely kept control of the flow of information and storage through the monasteries.
The reality of the working out of all this of course was a little messy at times, but the pattern held relatively unchanged up until the enlightenment, and is still a powerful force in the world.
Imagine the power when the vast majority of the population BELIEVE that you hold the keys to Heaven and Hell. See the Papal Seal. The Beehive looming over the Crossed Keys.
I suggest that one, if one can,go have a look at the Vatican. Check out St Peters and the Vatican Museum. The walls are covered in the glory of the Popes. Scenes of Kings Merchants and Peasants bowing to the Clergy. Vary few religious scenes. Interesting. And every old Roman building insight has the Papal Seal on it.
Of course there are many good and sincere believers in these religious organisations, but the propensity of the participants to willingly hand over their power and belief to what are always hierarchies led by one who claims God's (generic) Ear. (Insert deity or Ideology of your choice) has set you free, now here is what He/it tells me you must do. A bit scary!!
When one sees the rise of Fundamentalism in religion and /or Quasi religious thought (Ideologies). Hold your nose. There's a stink coming. And reason has left the building with the air freshener.