What if people were there to be sacrificed to the Primordials. People were enslaved by the Dragon Kings (or First Circle 'demons') and sacrificed by them to worship the Primordials. Perhaps this practice still goes on. The Primordials are no longer able to regain Essence from worship of First Circle Demons (if they ever were) but can still regain Essence if they sacrifice humans (who during the Primordial Age were the lowest form of intelligent life.)
In this history it's uncertain if the Dragons Kings have any place. There might not be any point in keeping them. Their existing role as 'benevolent dictators' who sacrifice humans to worship the Unconquered Sun who later Exalts them is one of the many weak points of Exalted.
