I have no answers, Arif, because who is to know if those old ancient cultures and the modern ones were/are influenced by consumption of plants or inhalation of gases or the hallucinations that come with food or sleep or water deprivation? And who is to know if they are meaningful symbolic dreams?
We can believe what we will, but we will never know the truth because truth will be something different for everyone who searches. And the final answers might be different as well.
And so we speak in riddles and go in circles and wish to dream.