I find it hard to accept the "you must be 7ft tall to play basketball" story about why people become good at something.
My own view is more something like what bodybuilders say. Some people find it harder to grow than others, but everyone can do it. And people who put effort into it will definitely be separable from people who don't, regardless of endowment.
Now as for who gets to be written into history books, there's a fair bit of randomness about that. A hard working person can well find that the only phd advisor who will take them wants them to work on some dead end. Or you may work on something hot, but other people will know it's hot, too, and they may well beat you to publication. Doesn't make you any dumber, but your name will not be enshrined in that theorem.
There's also a necessary confluence of factors that depends very much on your parents, specifically whether they figure out how to manage your development. Look at the current first-in-most-people's-minds genius, Terence Tao. Not only did his parents figure out that he was good at math, they somehow got him the right guidance. I'm guessing very few parents, even quite well educated ones, would know what to do if a guy like that turned up in their house. There's also the sheer randomness of whether you'll end up doing things that encourage the kid. Most parents, myself included, have very little idea of how to get a kid to do what's good for them. You laugh, unless you are a parent.