3 ideas
Desire that answers to no limit does not level off at satisfaction. It escalates until it destroys the body and the fortune that fed it. The same appetite that built his power is the one that kills him, so ruin grows out of success itself.
Read the domestic compound as a small copy of the realm. Ximen's bribery of court officials and his sale of justice as a magistrate follow the same logic as his wives' competition for favor, money and heirs. When power is bought rather than earned at the top, every relationship below turns into a transaction. Loyalty in the home dissolves the same way it does at court.
When many dependents' security rests on one patron's attention, they compete zero-sum through scheming, slander and violence against each other's children. Concentrating favor in a single capricious center turns the people beneath it into predators.