I would not disagree that in some places that certainly exists, but to me that seems like a plantation model of slavery which can only exist in cases where a particular high demand commodity, requiring a large labor pool, is present. In our history that would be sugar, cotton, tobacco or drugs. All of these require a whole sale demand in quantity which point to large scale commercial centers, that is cities (basic blocks of civilization). Once we start talking cities, we start talking bureaucracy, civil servant slaves. A pyramidal structure with Jann at the top.