I often see this interpretation that monotheism is somehow more “advanced” than polytheism, even Age of Empires suggested so but why exactly? Because Christianity and Islām became so popular?
Slight tangent: Even under the frame of animist religions, there is sometimes the notion that the more worshippers a god has (and the more devout), the more powerful that god becomes. So using this frame, monotheistic religions have a more powerful god to use to "conquer" other gods.
A slight tangent to your slight tangent: Monastic regimens look an awful lot like proof-of-work... Is the next step in facilitating the human-machine meta-minds minting AI crypto-religions?
Also, taking into account the earlier thread on Sci-Fi vs Sci-Fantasy, with a comment mentioning that science fiction tends to be current social commentary in the guise of the future: self-aware (and self-minting) currency a la Accelerando is an interesting analogy for religious, spiritual, cultural, and economic movements.
That is a later development. In the first millennium AD there were active attempts to export Judaism, the most famous result of which was the conversion of the Khazar kingdom to Judaism. And the very etymology of the word “proselytising” refers to Judaism making some inroads among other inhabitants of the Mediterranean.
As a prime example, many elements of Christmas such as the yule log originate from so-called pagan religions such as Norse.
And over the years Christians have persecuted many when their beliefs didn't agree with the dominant interpretation. The Romans were relatively tolerant of indigenous beliefs, as long as they didn't lead to rebellion.
In your life of plenty, poor people with nothing, were being ritually humiliated several times over, damming their mental health in hell. One god is less harmful to mental health.
Considering religion is psychological warfare in the absence of todays personal surveillance technological world, you would have thought some religions could be more forgiving for peoples misfortune, but is polytheism a classic example of power unchecked?
Hinduism was designed to normalise human deformities in a region struggling with environmental toxicity and poor health.
Christianity is best for a European climate, Islam is best for a Middle Eastern climate.
Religion was an attempt in the absence of simple items like pen and paper or infrastructure like schools and roads, to educate people through story telling & place names in order to protect them from harm.
Thats why all Christian churches are typically built on natural healthy springs and is considered holy water.
Christian churches are typically in the shape of a cross, Knights Templar churches are round.
And dont look a gift horse in the mouth when its smuggling gold to and from the Crusades! Has anyone tried that in their computer games or is that a knight mare?