This is a better way of putting the point I was inelegantly grasping at. The neighbor kid is just an industrious kid---they happen to be nailing up drywall, but it's not that nailing up the drywall is why they end up running Berkshire Hathaway (or whatever) later. It's that they're industrious, and have various other traits that---in some other context---would result in them doing whatever else.

Maybe they turn into the engineer who can extract water, if only for reasons of path-dependency. And in a world where water-extraction is a valuable industry, that path-dependent contingency will result in them maybe starting a valuable water-extraction engineering firm. But it's not that nailing up drywall as a kid made them uniquely qualified. It's that they were industrious and smart and had sufficient fortune and whatever else. Which is good, all that stuff is good.