My logic is more that since (I assume) Enlightened Mortals can exist in this system, there's decent odds that even if they weren't preserved through the changing of the world someone has reinvented them since and either written it down or passed it on.
Behold an enlightened mortal practicing a form of mystical martial arts, he is standing in front of you. Mortals would have less reason to come up with a style that works best for the Terrestrial Exalted and that mortals can learn if they push themselves to the limit.