Earlier this year Chris Dixon wrote what is mostly a good blog post, but sadly also a classic of blind northern California arrogance:
What the smartest people do on the weekend is what everyone else will do during the week in ten years...
Engineers vote with their time, and are mostly trying to invent interesting new things. Hobbies are what the smartest people spend their time on when they aren’t constrained by near-term financial goals...
Today, the tech hobbies with momentum include: math-based currencies like Bitcoin, new software development tools like NoSQL databases, the internet of things, 3D printing, touch-free human/computer interfaces, and “artisanal” hardware like the kind you find on Kickstarter.
It’s a good bet these present-day hobbies will seed future industries.
This statement is true within a bounded territory, but it has two zones of epic fail.
If by "the smartest people" you mean "the smartest young, single geeks in Silicon Valley with time on their hands but no idea how to party," then it's basically true, or close enough. It can even stay mostly true when you broaden it to "the smartest geeks in Silicon Valley."
But if by "the smartest people" you mean "the smartest people in Silicon Valley," you quickly run into the first zone of epic fail. Steve Wozniak did it as a hobby; Steve Jobs did it as a business. So the idea can only be legit if we assume Wozniak was smarter than Jobs. This is not only a dickhead thing to say, it's also extremely debatable.
That same problem becomes much, much more serious in the idea's grander zone of epic fail, which is the world at large. If by "the smartest people" you actually do literally mean "the smartest people," this statement falls from a lofty status of near-flawless truism — which it achieves when isolated to a particular subset of Silicon Valley geeks — down to a nadir of useless and near-total inaccuracy.
It can only be true if none of the smartest people are also uneducated; if none of the smartest people work on the weekend, or go to school on the weekend; if none of the smartest people are beset by war, famine, illness, or other distracting, weekend-filling forms of misfortune; and if none of the smartest people, anywhere ever, like to spend their weekends making music, making art, making films, or volunteering their time to feed the homeless, end various injustices, or make the world a better place in any other non-commercial sense, or indeed just having fun.
For instance, consider the Oscar-winning actress and budding director Natalie Portman, who first published her scientific discoveries in peer-reviewed journals while in high school. If she spends her free time geeking out about Bitcoin, Dixon's rule applies to her. If not, then either Dixon's rule is silly, or she is not one of the smartest people out there. But that would mean winning the top award in one of the most competitive fields in the world, attending Harvard, and publishing in scientific journals while essentially still a child would not be reliable indicators of high intelligence, while selecting a hobby which went on to become a big business would be a reliable indicator of high intelligence.
It doesn't take long to find many similar examples; and, as an experiment, I just googled "Natalie Portman charity work." Turns out there's enough there to win her another award. I hope she did all that charity work during business hours, because if it happened on the weekend, she's off that genius list.
It's good to pay attention to what the startup community talks about. You just need to take it with a grain of salt.