The reason is because the top engineers in Silicon Valley, whether they realize it or not, are part of a secret Guild. They are a confraternity of craftsmen who share a set of traits:

Their craft is creating software
Their tools of choice are C, C++, and Java — not Javascript or PHP
They wear ironic t-shirts, and that is the outer limit of their fashion sense
They’re not hipsters who live in the Mission or even in the city; they live near a CalTrain stop, somewhere on the Peninsula
They meet for Game Night on Thursdays to play Settlers of Catan
They are passive, logical, and Spock-like

They aren’t interested in tweeting, blogging, or giving talks at conferences. They care about building and shipping code. They’re more likely to be found in IRC chat rooms, filing JIRAs for Apache projects, or spinning out Github repos in their spare time.