To me the cool kids were generally the ones not doing very well in school so they would try to make it seem like their choice and adopt an "I don't give a shit" rebellious attitude. They don't follow the rules, that's why their grades are bad, not because they don't have the intelligence. (in their mind).

They would continue to do average or even worse but they would get the admiration of other kids for seeming to have confidence and control and rebelling against the establishment (teachers).

Of course not every one admired that type of behaviour, but the attitude of not caring about the rules is exactly what Donald Trump does. I think most of his life he has been pretty average at what he does, but he was good at self promotion. A skill he probably learned in the playground when he was struggling with school.

In this sense Trump is a "cool kid". He is just a rare example of the cool kid succeeding enough to become famous.

And for what it's worth, I don't think being one of the cool kids is something to brag about once school was over. In fact it generally becomes the opposite at that point. American TV often painted the cool kids as the most capable and popular in every way, but that is fantasy.

Musk on the other hand was not a cool kid, but he desperately wants to be one. He must have some issues from school when he was likely shunned by them or bullied and he is trying to make up for it. Explains a lot of his recent actions actually.