The if the aswer to, "can nobles ever question the nature of their society and learn to conclude that the system is bad?" question seems like it ought to be a strong "No", it's probably worth reading some history. Because... it's a bit more complicated.
Here in England, we still have nobility. We have a House of Lords who play a part in legislation, we have a King, we have a knightly order (The Order of the Garter), barons etc. Now.... You know England is a democratic country, and that our society is a bit more socialist-leaning than the US (a lot of people describe it in terms that our Conservative party are similar to the Democrats, and then the largest opposition are further left of that, and the closest analogues we have to Republicans in policy are considered far-right fringe parties). So... how does that work?
Well... because historically, we've had nobles and wealthy people who get educated, spend a bunch of time thinking (because they can, because they're not toiling in the fields all day), and then decide, based on that education, that progressive values are appropriate, better for society or more efficient. They can do this precisely because they don't need to earn money, and so their decisions can often be made without being swayed by lobbyists or a personal vested interest in specific industries. There's also a lot of social pressure on nobles to assume positions of leadership, such as being officers in the army, going into politics or becoming athletes, artists or at least patrons of the arts. (The late Queen's sister is an olympic medalist, and most of our royal family have served in the Armed Forces).
So, for example, it was a group of barons all getting together who forced King John to sign the Magna Carta, the document announcing that everyone has rights and that the King no longer has absolute power. This one was largely in their own favour; they were sick of the King having absolute authority to demand whatever money and resources he wanted of them without needing a reason or anything. So they made a document that basically says "All English people are free and follow these laws. Anyone accused of breaking a law has right to a fair trial"
But then it was also a Noble, Earl Grey, supported by many other Lords, who proposed the act to abolish slavery in the British Empire. There were financial reasons of course, (slavery becomes less profitable over time because people can have babies so you don't need to buy more, and yes, that's horrible, the whole concept of owning people is horrible) BUT there was also a legal and moral component that many of these nobles brought up, like "slavery is horrible", mixed with "wait a minute... our Magna Carta...the one that says Queen Victoria can't take all our stuff for no reason....says ALL English people are free, right? So... if you brought a slave to England, and they lived here, they legally would become an English citizen and therefore free the second they were living in England.... and like... if our laws are meant to apply to our colonies too... surely that means....huh."
See, the thing about Nobles that people from countries without nobility maybe aren't aware of, is that in some ways they're sometimes better than capitalist billionaires, because their status and power is established and assured, and their responsibility is simply to maintain it. If the only way to get political power or agency in your society is to get rich by exploiting others, coming up with ways to squeeze more work and profits out of people, then you end up with the people in power being those who have exploited people, and must continue to have money to have that kind of power, leading to a vested interest in their own profits, but the advantage of having people inherit their lands, title and right to speak in court or government is that they don't need to have any stake in any businesses; they can hypothetically be above lobbying.
Of course, it's not always the case, and really it's not an ideal solution, because as I mentioned before, it leans heavily on some of the nobility being good people who get educated and then use their power to do good things, or at least just generally being motivated for the country itself overall doing well and being a good place to live rather than motivated by their own businesses doing well. Nobility can still be really terrible and hog resources, or get tied up in business, or neglect their responsibilities, so it's kind of all the luck of the draw. It's still not as good as a perfectly meritocratic society where lobbying is outlawed, obviously! Knives Out, while not a movie about nobility, is about inherited wealth, and perfectly shows how the Thromby family are sort of charitable towards their "servant" (but also dismissive and clearly think they're above her) and think they're good people for it, only to immediately turn into savage back-stabbers when their wealth is under threat. Nobles exist comfortably at the top of the pyramid of needs, and have the power to philosophise and so could do good... they could, and sometimes they do.
But the Romantic dream remains, because some of the nobility have historically been poets like Lord Byron, or great scientists like Sir Isaac Newton, been patrons of the arts, or been part of great social reforms, so naturally writers are drawn to that idea of the beautiful kind-hearted noble who can both enjoy the luxurious aesthetics and lifestyle for the escapism, while also being a morally good protagonist who participates in high-stakes adventures and does good things supported by servants who feel blessed to have such a benevolent master and proud to serve them.
