Relentless alone isn't enough. "In any interesting domain, the difficulties will be novel. Which means you can't simply plow through them, because you don't know initially how hard they are; you don't know whether you're about to plow through a block of foam or granite. So you have to be resourceful. You have to keep trying new things."

Hapless is the opposite quality to aim against, and it implies passivity: "to be battered by circumstances — to let the world have its way with you, instead of having your way with the world."

The best metaphor is a running back: "not merely determined, but flexible as well. They want to get downfield, but they adapt their plans on the fly."

Resourcefulness is the recipe for startups specifically because the obstacles are external. In writing or painting the obstacles are internal — your own obtuseness — so the recipe there is to be actively curious instead.

Being relentlessly resourceful is "definitely not the recipe for success in big companies, or in most schools," where the recipe is some longer, messier combination of resourcefulness, obedience, and building alliances. Young people who've always been under authority often have a latent capacity for it that just needs to be drawn out.

Use it as a screen: ask whether you're relentlessly resourceful before starting a startup, and ask it of anyone you're considering as a cofounder. The size of the pool of people with this quality is what bounds how many startups can exist — not any economic ceiling.