No one builds wealth entirely on their own. And the people who are the most "self-made", as in were born into poverty and ended up in upper middle class or high

No one builds wealth entirely on their own. And the people who are the most "self-made", as in were born into poverty and ended up in upper middle class or higher income levels, the numbers of people like that are so low that they fall into the noise you'd see in any random distribution. There's no difference between these people and millions of others, other than just getting lucky.