What would be the essence of these castes when they haven't suffered corruption?
The Spartan caste hierarchy is topped by the healthiest individual.
The Genovesi hierarchy is topped by the friendliest individual.
The Athenian hierarchy is topped by the wisest individual.
I have the most trouble formalizing the Genovesi - if the theory is somehow wrong, it's because I've misunderstood that part. Right now, I'm thinking of them as keeping score with money, rather than being about riches per se. The best Genovesi makes the most deals and wins concessions in negotiation. They're socially skilled, which cashes out to being able to befriend widely and easily. I invite you to try to change my mind on that, however.