The priesthood was a hereditary position. Aaron's sons are to continue the priesthood and are considered holy. In those days, it was primarily the elite members of the priesthood who communed with the divine. That elitism was hereditary. These constructs helped define people's roles in society, and so they helped keep society stable.
Time passes, however, and things change.
And, at least at this moment, it appears that the sweep of history favors democratization. All show a push to give authority to an ever-widening sphere of people. Our religion has somehow managed to make that transition. We have transitioned away from a high priest who channels divine intentions. We have transitioned to a state of individual prayer and study, and individual rapport with the divine.