At least Commander Taon Melin still had hope of advancing to expert pilot.
By becoming a demigod, Taon eventually had hope of becoming a god pilot. No matter how improbable it was for him to reach the end of this extraordinary journey, his opportunities were still greater than that of Melkor!
Melkor did not harbor much envy or jealousy towards his fellow legion commander. Not everyone was as talented or fortunate as Commander Casella Ingvar, who was able to combine leadership with her own individual progression.
Not every Larkinson needed to become a high-ranking mech pilot in order to feel validation. There were plenty of other ways for people like Melkor to make himself useful to the clan. His role was just as indispensable as that of the mech pilots that sacrificed portions of their humanity in order to attain their version of godhood.