I tend to see a lot more 30+ founders outside of the bubble around high-profile, high-tech businesses, which naturally gets a lot of coverage on sites like HN.

I tend to see a lot more 30+ founders outside of the bubble around high-profile, high-tech businesses, which naturally gets a lot of coverage on sites like HN. Also, they're talking about startups that were in good enough shape to raise VC funding. It's possible that a lot more than 1 in 7 of all startups is founded by under-30s but that the lack of experience means those startups disproportionately fail to reach a stage where they are worth funding by VCs.