Royalty only comes with a specific kind of worldview and expectations if you are raised (IE trained) to be royalty as you grow up and have those expectations.
A baby princess, taken from her parents and never told she’s royalty, isn’t going to naturally grow up expecting to be treated like a princess. Look at the story of King Arthur, or any fairytale where the prince or princess is raised as a servant.
Their outlook and expectations are fundamentally different than those who were raised as royalty. This ironically makes them exceptionally good at BEING royalty when they must take the throne, because instead of being taught to expect to be treated as divinity, they have learned to be humble.
Its nurture, not nature.