And I'm sure that's a great comfort to the vast number of people who are born with every bit as much potential for greatness as <insert personal favourite genius, celebrity, or billionaire here>, but never have the opportunity to realize it due to crushing poverty.
They may never be able to achieve even modest financial security and live in constant dread that they'll lose one of their 2-3 jobs and be on the street, but hey, they can define success as meaning a family that loves them, so that makes absolutely everything OK! /s
No idea why this would be downvoted, this is absolutely true - there is not just one version of what a successful life looks like. Deciding how you define success is a principle part of forming yourself as a person.
While this sounds great, it's a bit like when people say you can "choose what to believe". You cannot, in fact, choose what to believe. You either believe something or you don't. Similarly, with feeling successful, you either do feel that or you don't. It's not really under your control.
But what you can do is realise that things aren't always under your control so not to worry about them. Instead just concentrate on things you do have and things you can do. You have the power to be useful to society so do that. You have the power to do good things so do it. How you feel doesn't really matter.
They may never be able to achieve even modest financial security and live in constant dread that they'll lose one of their 2-3 jobs and be on the street, but hey, they can define success as meaning a family that loves them, so that makes absolutely everything OK! /s