A lot goes into it, and luck is a major factor. But it also requires some intelligence and self control. How many athletes just lose tens of millions of dollars simply because for reason they can't stop spending it?
I don't think so, because for me success is a thing that needs thorough effort and action to be achieve. Intelligence and talent plus hard work are a must to become rich and not by chance. If you are dependent with luck and doing nothing, being rich is rarely be achieve.