Minus the under 10, I think there is some truth in the pattern from the point of 16+. Hacker News/Y combinator primarily attracts entrepreneurs,hackers,engineers...people who are constantly learning based on self-interest. 26 is the average age for a Y Combinator alumni and 26-30 is also the majority of users in this toll. Essentially what I'm trying to say is I think this is a reflection of ambition dwindling with age based on the general overall population.