It's the literal opposite of rare. It would be rare if people were born preloaded with all the knowledge of previous generations. As far as I know 100% of people are born without knowledge of deity concepts and therefore must be taught it in order to align with theism, monotheism, polytheism, atheism, or autohteism—yeah, there's more, but that covers the main ones of gods, singular, many, none, and self.
I think this discussion is using philosophy, ironically, to disguise failures in literacy.