Because the bureaucrat had to prove their merit among the whole population while the rich entrepreneur just had to prove their merit among other kids that were privileged enough. Just think of Bill Gates that went to probably the only school that had a computer in the world.
In ancient China they even went so far to castrate bureaucrats to prevent cross-generational cronyism.
> Why limit Elon Musk
Because he is using cool goals like travelling to mars to motivate his workers to work themselves to exhaustion while ignoring safety measures? He acts exactly like capitalists of the industrial age. The difference is that his workers do not lack money for sustenance, but a purpose in life.