The problem is the time that capitalism requires just to survive leaving very little extra time to do stuff even for a genius.
It takes not just genius to do great things but a mountain of free time and resources, which the aristocrats had in spades back in the day.
Elon Musk is one of the few people with the confluence of all of these factors and is doing great things.
He has to understand Rocket Science and Astrophysics to enough of a degree to communicate and make decisions with other Astrophysicists and Engineers at his space company.
He has to understand chemistry and mechanical engineering to enough of a degree to communicate with the lead engineers and make decisions at his EV company.
Not to mention how he got his start with Pay Pal and understanding computer technology and encryption.
He may or may not be a 'genius genius'.
But there's zero doubt in my mind that he 'ain't no dummy'. :)