If we speak in broad strokes and ignore fuzzy edge cases, we can divide people into three different levels of social agency throughout history and across societies:
Slaves are people who can't own property, don't have much social autonomy, and are treated as property themselves. Someone else has authority over what they are going to do, what possessions they get, who they associate with, and so on.
Freemen are people who own property and own themselves, in that they have and maintain possessions, decide who to associate with, make plans, improve themselves, trade in the market, and so on, but don't command groups or lead social phenomena.
Aristocrats are people who can own chunks of social reality, act with full agency independent of existing social institutions, command groups of people, participate in government leadership, do bold or contrarian research or innovation, and so on.
For example, these distinctions are more or less played straight and formally in the pre-christian germanic world, and they show up in one form or another in most societies.
Our own society attempts to do away with these distinctions and treat everyone as freemen with some aristocratic privileges and expectations, but I think they are still there if we interpret the above definitions as natural rather than normative statements.
For example, I know people who are simply not responsible enough to own property. I don't mean in the sense that they shouldn't be allowed to, but in the sense that they abuse and destroy anything that comes into their possession, including themselves. Their bikes get wrecked, their tools get lost and dirty, their space gets cluttered, their computers get filled with viruses, they can't hold jobs, and are always either lost or a dependent of someone else. Thus in some natural law sense, these people can't own property, don't have social autonomy, and have many of the other properties of slaves. I think this is what Aristotle meant by calling some people natural slaves.
Most people aren't like this; most can generally manage their affairs and do fine in society as freemen.
Then there are other people who seem to have a level of agency, discipline, competence, and social connectivity that allows them to automatically command authority, create and manipulate parts of social reality like companies and subcultures, take bold and independent action, plot strategically, and generally act as protagonists in history. That is, they have the actual substance of aristocracy as defined above, if not its formality.
We can imagine intelligence, agency, and discipline varying independently, but they tend to be correlated enough that we can roughly characterize a bottom end of society as unintelligent, undisciplined, and lacking in agency, and a top end as intelligent, disciplined, and agenty. This correlation, collapsed down to a single dimension, gives us the above hierarchy.
On the other hand, I suspect that agency and discipline are partially trainable. People who have never had to fend for themselves, never had to command others, never had to maintain tight standards of discipline under command, seem to have lower agency and discipline. Those who have undergone such training have higher agency and discipline. We have previously mused about the lack of aristocratic training in the modern world.
On the gripping hand, some people are just never going to make it as freemen, and most freemen won't make it as self-actualizing aristocrats, within practical limits of training. Further, there might be something inherently elitist about the aristocratic mind, such that a society of entirely aristocrats is impossible.
With that in mind, and considering the general value of formalizing in social understanding the actual realities of nature, we can see that formalized social rank with recognized powers of agency could actually make sense. For example, formally specialize training and networking by expected social rank.
What a proper twenty-first century system of formal social rank would look like I don't yet know, but having a coherent framework with which to consider the possibility is occasionally enlightening, especially if we are interested in constructing alternative social systems for ourselves.