Anyone can be an elite performer with enough training and effort. Not everyone can be top 10 though. At some point genetics plays a role. But to be _elite_ does not imply being top 10. If you are ranked the 500th professional tennis player you are far from being a Nadal or a Federer, but that’s still an incredible level of performance. There’s only 500 other humans on the planet that can match up to you.

> that there's ceiling on how far one can go with grit alone.

This is a tautology. Of course there's a ceiling of how one can go with [X] alone, (in fact, given any [X]). It doesn't pour water on the theory at all, it's just an uninteresting and fatalistic point of view.