Centralized power used to be harnessed by religous leaders, and they used it to wage wars and commit mass murder.
Did centralized religon eventually morph into early forms of government?
kings, for example, being divinely chosen to be the leader?
I think it may be one of those chicken and egg scenarios. Either way historically the state and religion have always had a close relationship. Hard to say.
I can’t be absolutely sure, but the way I see it is that religious relationships were derived from experience. In other words, man saw rain and not having any real scientific knowledge believed that it was the product of multiple gods or a god. In other words, they applied supernatural casaulity to events they couldn’t otherwise explain. I think men took advantage of the creation of religion as a means of securing power.
back when man believed all objects were animated by ‘spirit forces’, any success of a man vis being a great hunter or warrior could easily spun off as a story of his being favoured by the ‘spirits’ or gods. its a short skip and a jump to a divine right of kings, etc.
Nope, this type of stuff only works if people love to introduce very simplistic narratives to subsidize a preferred aesthetic position/ are hyper-focused on a very small aspect of life and construct narratives to suit that area.
You mean thinking like the typical westerner? 
But anyways, I think it would be more correct to say that in recent history the state, through"democracy", has taken over many of the roles of religion and tradition.
Every society that I know of that got past the tribal stage into a state was a monarchy, and every monarch claimed to be the son of a God. In this sense, the religion-turned-into-state scenario is nearly certain. I can only add that, for a Sitchin believer like myself, the claim of, say, the Japanese Emperor to be the son of God is not so farfetched and, thus, the transition into a state could have been inevitable.