I actually believe that for people to "keep their feet firmly on the ground" you need a centralised culture of COHERSION to begin with. Like, if you don't follow this belief exactly as it has been presented (for example: The Ten Commandments), you'll be thrown out of heaven etc. But there never was such a culture of cohersion within Mazdayasna, so the religion was always more welcoming, syncretic and decentralised than the Abrahamic faiths. Again, Zoroastrianism, especially the folk religion, is far more Hinduist than Abrahamic. There is not even a priestly category in Zarathushtra's teachings. Even intolerance towards non-Zoroastrians in Zoroastrian history is more a priestly than a dogmatic phenomenon (the Sassanid persecution of Christians and Manicheans etc).
I often use stories to help my (toddler) daughter understand concepts and help guide her learning. I can imagine in ancient Persia that early Zoroastrians would have struggled to expain Zoroastrianism to the general Polytheistic Persian poplulation. A peasant with no education and unconcerned with philosphy is bound to liven the stories up. What I don't understand is why the priests themselves didn't keep their feet firmly "on the ground"? Was there some sort of mass conversion?
These stories are not bad unless they become the beliefs themselves rather than a means of learning them.