Attainment of Rank does not necessarily show skill, and almost all of the armor is unlocked by Legend Rank. The only 2 bits left are the 'tusks' for Gungnir Helmet (Unlocked at Mythic) and the haunted helmet (unlocked at Inheritor). In essence, there is so real advantage of getting beyond Mythic rank and most people do it passively rather than actively trying to get up. The extra ranks are to keep the pros happy and to give people bragging rights.