It's probably in the interests of states to have strong families since the family is where humility and obedience are taught. It's the family which provides the blueprint for authority within the monarchical/imperial state. Conversely the monarchical/imperial state provides - at some remove - surrogate family-figures.
Hereditary succession reminds us that most subject positions aren't chosen, but must be borne. That for building happiness continuity is more important than improvement. Happiness arguably comes from exchanging meanings within an economy of symbols you have reason to value - that you've been acculturated to - more so than from short-term material progress. (And, just to join the dots, that's why the US should have a monarchy again.)