"I want to stress the importance of being young and technical," he stated, adding that successful start-ups should only employ young people with technical expertise. (Zuckerberg also apparently missed the class on employment and discrimination law.)
"Young people are just smarter," he said, with a straight face, according to VentureBeat. "Why are most chess masters under 30?" he asked. "I don't know...Young people just have simpler lives. We may not own a car. We may not have family."
Chess masters do commonly mention noticing a decline in what might be called their raw processing power as early as their late 20's, but most results peak in their mid '30's [2] and some peak in their '40's. (And should spending your time playing chess be a marker for intelligence?)
But wisdom is in part knowing what is worth working on (such as should you spend your time playing chess), and that is generally accepted to increase with experience. For example, the average age of entrepreneurs at the time they founded their companies is 42. [3]
[1] https://www.cnet.com/news/say-what-young-people-are-just-sma...
[2] https://theconversation.com/anand-vs-carlsen-the-age-effect-...
[3] https://hbr.org/2018/07/research-the-average-age-of-a-succes...
EDIT: Fixed year of quote reference.