Someone said a "well conceived myth". I agree . It was conceived to controI the many and enrich the few.
It's like if I took my 3 year old son and told him there is a monster in the closet. He WILL believe me. As long as I explain it to him in a totally serious manner and with a straight face. Once I get him to accept that "fact" I can use it to manipulate him any way I want. For example: pick up your toys or I will let the monster out, or - eat those vegatables or the monster wont be pleased with you!! If he, along with every other child in the community was raised to believe in the monster, it all seems perfectly normal. What if you also taught these kids that anyone who questions the existence of the monster or tries to open their closet is evil and will be killed by the community for trying. Now you've added a heavy dose of fear to the mix and it's even easier to get people to obey you.
With this illustration in mind remember that historically only priests and clerics were able to read and write. This left 99% of the population throughout the ages as vulnerable as a 3 year old, ripe for easy manipulation. As time moves forward and we have progressed - that 99% is steadily dwindling. Add to that access to the internet, and people are not so easily duped.