Imagine if Y Combinator owned and ran San Francisco. Too much traffic? That’s bad for business. Highway 101 would be triple- or quadruple-deckered, and the metropolitan area might have a dozen subway lines, more like Madrid’s or Osaka’s networks than the BART as it stands. Heritage buildings? They’re nice, but this is a tech town. Skyscrapers would fill the entire peninsula. Instead of wealth taxes on billionaires, the city might even cut taxes to encourage more founders and companies to move th...