Hans Hermann Hoppe's main argument in favor of traditional monarchy is that the King tends to consider his domain as his personal property and the inheritance of his sucessor. He has skin in the game and self-interest in the prosperity and stability of the kingdom. Longterm and short-term. That is how things should work - the interest of rulers and subjects should be aligned.
Compare that to a politician who only cares about the next election and how his popularity polls. Why do you think every single demockery falls into a debt trap or population replacement spiral.
It can be a biased indicator and is no guarantee, but insider ownership and founder's administration tend to be great indicators for a company's prospects for instance. That is why a company like CNQ can grow and prosper so fast while state-owned companies tend to flounder even with unfair advantages like a monopoly on a line of business or resource. The person running the government(or business) should have clear personal interest in its success.