Well, it still only says that humans have less trouble wrapping their head around that, than about "likely".
Note however that a lot of historical "polytheism" was really just a bunch of almost monotheistic cults giving each other leaway. Marduk could probably tell you at length about the monolatry in the cult of Marduk, but we have quite the extensive collection of borderline monotheistic or monolatrous prayers to just about every single god in the Mesopotamian pantheon. Think, along the lines of not just "you are the greatest", but basically skirting with outright denying the other gods. Or even in Egypt, that 42-point "I did not" list only forbade denying the patron god of your city, but the others were fair game.
Basically don't think of historical polytheism being really a case of everyone worshipping all gods and respecing their jurisdictions. Each family, and at a bigger scale each tribe or city, had their one or two divine parents which they primarily worshipped for everything. And they only grudgingly allowed the other families/tribes/cities to have their own divine mommy and daddy.
The complex pantheons and hierarchies of the gods were more for diplomatic reasons, and more of a reflection of which city is currently subordinated to which other city. It was not what the average Joe had much of an interest in, when actually praying for some divine favour.
And again, almost every god was worshipped by some people for everything. E.g., even Seth, god of war, chaos, destruction, foreigners, the deadly desert sun, and redheads (hmm, noticing a pattern there

) had a thriving side-business in fertility medallions and prayers, both for agriculture and for how many children you want.
Probably that's the most mnemonic way I've heard it put. The gods were really substitutes for parents, and really nobody imagined them as having a dozen moms and a dozen dads.
So, really, is it a case of people really being that fond of polytheism, or being really just a bunch of monotheists at heart (well, ok, plus their God's wife or husband) that used to give each other some space?