For this writing, I will use the classical understandings of these terms. Both mono and poly theists have developed some radicalized fringe elements that are, for lack of a better term; 'insane'.
Monotheism is the belief in one 'God'. Usually this 'one God' is all knowing, distant, masculine and easily offended. Polytheism, as described by monotheists is the belief in many gods. That is an often intentional inaccuracy.
Those that are labeled "Polytheists' many times understand and accept the ubiquity of that which we call 'God'. Polytheism and Paganism are often used interchangeably. They are the belief/knowledge that which many call 'God', is actually unified spirit or energy that has infinite expressions. There are no 'mountain' Gods, there is God as this mountain. There are no tree gods, there is God as the tree. There are no storm gods, there is god as this storm. God as this blade of grass...god as the snow leopard, god as the antelope. Unending expressions of the universal spirit of all. God expressed as the individual thing and God expressed as the Universal whole. The subtle cognitive shift in understanding of pagan or polytheistic beliefs is to comprehend that the assertion is not of many gods. It is all things as an expression of 'God'.
All indigenous peoples be they from Africa, to Asia, to even Europe and the Americas have their own earth based spirit systems of knowledge and practices. These ancients knew the cosmos, revered the seasons and their relationship to the cosmos. Earth was mother god. The heavens were records of the movement of the cosmic bodies and viewed as God expressed in the seasons. Animals were known for their unique spirit(s) and others were seen as reflections of god and oneself.
However, with the ascendance of Greece and it's 'pantheon of gods', and then Roman paganism which was derivative of the Greeks. The Romans ultimately postulated that Caesar was god. The direct personal experience of that which is called 'God' began to become imaged in a narrow, exclusive manner and projected outside of the experience of Oneself. People lost the motivation and ability to contemplate the divine within their own experience and began to project their own inner, sacred divinity onto statues and 'leaders' and books. They became supplicants, not sovereign individuals with their own direct connection to the sacred beingness of themselves and all things.
The cosmological lineage of western religious/spiritual language and understanding is rooted in Africa. It flows from Egypt/Nubia, through Greece and Rome all the way to the British empire into America. The Hindus in India were always Hindu, the Taoists of China and the Asian continent were always Taoist. However, western philosophy and spirituality is derivative of African philosophy and spiritual thought. It is African with an added twist, or in some cases flat out corruption of the original core essence. That is not to say that Hindus, Taoists and Native American religious systems didn't develop outside of African influence, they did. However, the fundamental core of the Abrahamic religions of Judaism, Christianity and Islam are African originated in their cosmology.
From Africa, Europe to Asia and the Americas and Pacific Island cultures, shamanism was practiced. Shamans understood the movement of the cosmos, could perceive the subtler energies of nature, humans and animals. Shamans understood that all was a manifestation of One spirit (energy) and that this Universal singular spirit needed to flow. Dis-ease, both physical, emotional and mental could be traced to the source as blocked Universal energy, energy that the ancient Chinese called Chi. Acupuncture is an example of the assisting the flow of Chi. Shamans were invaluable to the tribe for healing. However, just as in any gathering of humans, the kind of power the shamans could hoard was ripe for abuse. The Mayans are an example of this. The Mayan culture was ruled by a shamanic priesthood that possessed an intricate, predictive knowledge of cosmic events and planetary transits which they used to keep the masses of Mayans in a superstition fueled ignorance. The Mayan culture collapsed suddenly after almost a millennium reign. Ecological disaster was the main culprit. The Mayan people didn't possess the sacred self knowledge to sustain themselves.
Shamanism is making a return. However, this time it will be a personal self-knowing, shamanic philosophy. We're becoming our own medicine men and wise women. We're nearing a critical mass of humanity that wants to know 'God' for themselves, not dependent on any intercessory priests or religious dogma. Humanity in the generations to come will become communities of independents, self responsible, devoted to personal integrity and each other. Know Thyself will be the dominant spiritual pursuit. Our minds will re-unite with our hearts and we will truly become One. Mono-theism or Poly-theism will not matter anymore. We will know All is One, with infinite expression.
I don't wish this...I know, I've seen it.