Of course not everyone can become an Olympic athlete just by trying. And of course not everyone will be the next Steve Jobs or Zuckerberg no matter how hard they try, either. That's not the point.
The point is that most people don't even bother trying, and if you try, if you even just show up on a regular basis, you can probably reach above the 50th percentile in anything.
I would bet that almost anyone who puts a concerted effort into any endeavor could get to the top 25th percentile in just about anything. Hard work and hustle can bridge a lot of gap that natural ability and luck may create.
But if he is somehow just now coming to some epiphany that hard work can't trump luck and/or natural advantage (either thru ability or status), then my answer is: "Welcome to the real world." You need to temper any goals you have with maturity and realism. I'm a terrible basketball player, but I'm sure if I spent 1hr/day every day playing pickup for 1 year, by the end of a year, I'll be better than at least half of the regulars. But if my expectations are that I'll be able to dunk and beat Michael Jordan, I'd be delusional.