Luskin: “Evolution moulded our minds and bodies to the life of hunter-gatherers” (p. 378) — then there’s no reason to expect that we should need to evolve the ability to build cathedrals, compose symphonies, ponder the deep physics mysteries of the universe, or write entertaining (or even imaginative) books about human history. Why should these things evolve? He said it, not me: “Frankly, we don’t know.”
Generally, monotheism is favorable to a high level of organization, including complex theologies that don’t just morph a lot but are only changed with much deliberation or controversy. But did that state of affairs evolve so as to foster “cohesive unity,” as Harari suggests? Hard to say. Religion — especially propositional religion, like the monotheisms — can foster either unity or disunity. Monotheism has not been a force for unity in Northern Ireland or the Middle East.
The oldest type of religion was probably a form of naturalism. Non-naturalist religions are better accounted for by revelation.
The “evolutionary” view (Darwinism, in fact) is often portrayed as a sort of liberation but people may be rather surprised to discover exactly what that liberation is.