Personalities are built; you're not born an introvert. Anyone can be built into a leader; go join the Marine Corps if you don't believe me.
I've met Marines that were assholes so I'm guessing that 'join the Marine Corps' isn't as great advice as it first appears. Recently a Marine drill instructor was implicated in the abuse of Muslim recruits. That isn't a good leadership skill for the corporate environment. Your notion is too simplistic. It doesn't apply to everyone. It applies to some people but not all.
People lie on a spectrum in terms of abilities and personality. Not everyone can be molded to have the requisite knowledge/personality type to command high pay. It's simply not possible. Just take extreme examples and one can easily see this.
A Drill Instructor being a dickhead is also a choice. It doesn't make him any less able to be a leader. My point was, joining the Marine Corps turns weak individuals into respectable men that can command dignity and respect into people. What they choose to do with that transformation is up to them.
Peoples' personalities are also not always so malleable. My wife is a psychiatrist and she deals regularly with people who simply do not have the choice to change. Forces inside their brain are beyond their conscious control.
The Marine Corps sometimes turns weak individuals into respectable men. And sometimes it pumps out assholes. It doesn't work for everyone. This is obvious.
I can say that not only would I never get anywhere with math at that level, but some of the related mathematical pages on Wikipedia surpass my ability to even tell if they are real or the work of cranks.
For any random person, there are things they can't do or learn because of the way they're made, any more than a cow can do calculus.
What's deceptive is that people constantly tell you that you must believe in yourself. But the reason isn't that believing in yourself is sufficient for success - the reason is believing in yourself is necessary to succeed so everyone who is successful attributes their success to that.
It may take them 20 years to learn math from the ground up, but they can do it. Saying someone can't do something is bullshit. That's sheep mentality.
There's a substantial body of research suggesting otherwise.