PALO ALTO, Calif. — A perfect California day. The sun was shining, a gentle breeze was blowing and, at a Silicon Valley coffee shop, Rep. Ro Khanna was sitting across from one of his many billionaire constituents discussing an uncomfortable subject: the growing unpopularity of billionaires and their giant tech companies.

“There’s some more humility out here,” Khanna, D-Calif., said.

The billionaire on the other side of the table let out a nervous laugh. Chris Larsen was on his third start-up and well on his way to being one of the wealthiest people in the valley, if not the world.

“Realizing people hate your guts has some value,” he joked.

For decades, Democrats and Republicans have hailed America’s business elite, especially in Silicon Valley, as the country’s salvation. The government might be gridlocked, the electorate angry and divided, but America’s innovators seemed to promise a relatively pain-free way out of the mess. Their companies produced an endless series of products that kept the U.S. economy churning and its gross domestic product climbing. Their philanthropic efforts were aimed at fixing some of the country’s most vexing problems. Government’s role was to stay out of the way.

Now that consensus is shattering. For the first time in decades, capitalism’s future is a subject of debate among presidential hopefuls and a source of growing angst for America’s business elite. In places such as Silicon Valley, the slopes of Davos, Switzerland, and the halls of Harvard Business School, there is a sense that the kind of capitalism that once made America an economic envy is responsible for the growing inequality and anger that is tearing the country apart.

On a quiet weekday at a strip-mall coffee shop, the conversation between Khanna and Larsen turned to what went so wrong.