SV start-ups need bright shiny twenty-somethings for their "About us" pages and their IG lifestyle feed, with a few wise old thirty-somethings to ride herd on them.

It leaves room for the forty-something and fifty-something VCs to do what they enjoy, which is pretending to be the team coach.

Put in some wrinkly old guys - or worse, some old women - and there goes your brand identity.