I never said polytheism was new. How could anyone think that?
Read my post. I'm saying that "neither monotheism nor polytheism" is new.
Hinduism is neither monotheistic or polytheistic, it is very difficult to classify in those terms. Your idea of a "one deity that is everything and has all these facets" is a core concept of Hinduism; Brahman is the total sum of all existence, an infinite consciousness that is the spiritual essence of the universe. For the Bhedabheda school, Brahman is the actual universe itself.
Along the same lines, Buddhism is neither monotheistic or polytheistic in any meaningful sense. While the laity worships deities and arhants, the
sangha regards the whole question as aside the point, as the goal is to become enlightened -- a process during which, for the most part, the monks generally stop caring about cosmology.
Maybe you ought to read up on it.
And religions are not all hierarchical and conformist. Before Christianity in Europe, every village had its own religion.
Yeah, not so much.
The earliest band-level societies very likely had unique deities. As they developed into larger and more organized societies, these developed into polytheistic religions, which were in part combinations of those smaller societies. As smaller groups were incorporated into larger ones (coerced or voluntary), in some instances they brought their deities with them.
For example, in ancient Rome and its conquered territories, there was a constellation of deities, and individuals could choose which gods to worship or sacrifice to for specific benefits. An individual might sacrifice to Mars before setting off to war, Juno for fertility, and Neptune before setting sail. Other aspects were essentially universal, such as respect for the Vestal Virgins, common practices for sacrifices and divination, and classifying Caesar as a god on Earth.
Similarly, the Huns did not have atomized religious beliefs. Today, we refer to their religion as Tengrism, which is a type of shamanistic sky- and earth-worship. I.e. it wasn't the case that 10 Hun villages would believe in 10 completely different deities or 10 completely separate religious practices. The same for the Celtic religion; as a community they shared myths, and thus were aware of a variety of deities. They had some fairly consistent ideas and practices, e.g. common ideas about life after death, a priestly class (the druids), a common pantheon, and so on.
In tribal, stratified and civilized societies, most religions were quite hierarchical (which is not the same thing as "conforming to norms, ideas and myths"). Even matriarchal religions tended to have a clear hierarchy, with gods on the top, and spirits and humans as lesser entities. Early stage tribal societies probably started forming around 14,000 years ago, whereas exclusive monotheism is more like ~2000 years old. (Maybe 3000 if Zoroastrians were exclusive, I'm not sure if that was the case.)
We should also note that Judaism wasn't exclusive in the way it is today. To wit, Jews did not think that other deities were fake -- rather, they believed that those other deities existed, but that YHWH was the most powerful deity above all deities, and the Jews were YHWH's chosen people on Earth. The intolerance, exclusivity and outright rejection of other religions was a Christian development.
