The Boy Bosses of Silicon Valley Are on Their Way Out

Leaving as billionaires, they have emanated Silicon Valley’s relentless positivity. Pinterest “is just getting started,” Airbnb “is in the best hands it’s ever been in” and Instacart has a “enormous opportunity ahead,” the founders wrote. Both Mr. Mehta and Mr. Gebbia said they had plans for new projects.

Investors say they…