Where do you get small fraction? That's not true at all. I can't even see either of your examples as having more, let alone a multiple.
Anyway, the wealthiest western capitalists aren't even accounted for. "author Malcolm Gladwell estimated the value of Rockefeller's fortune at its peak, in today's dollars, at $318.3 billion" [2] It's divided among the family at this point though of course.
But of the living individuals that we know (Bezos/Gates/Musk/Zuck), and have accurate info for, your statement is not true.
[1] https://money.com/vladimir-putin-net-worth/
[2] https://www.foxbusiness.com/markets/how-rich-is-the-rockefel...