Polytheism is arguably less plausible than monotheism, since polytheism removes the illusion of mystery and transcendence. The society of gods becomes an obvious mirror of the human society that worships them, which gives away the game of religion.
As Yuval Harari said, the ancients may have thought of their religions not so much in intellectual terms of what’s factually true, but in terms of what we’d think of as corporate branding. If you practiced a certain religion, you were on that team and identified yourself with that brand. It was like being an Apple or a Google person, or a Marvel or a DC one. Polytheism made that social function of religion more obvious by reflecting the character and social hierarchy of the population.