Silicon Valley’s luminaries woke up Wednesday morning to a darkened new global order, one that the ceaseless optimism of their tech-powered visions seemed suddenly unable to conquer.

Across the technology industry, the reaction to Donald J. Trump’s election to the presidency was beyond grim. There was a sense that the industry had missed something fundamental about the fears and motivations of the people who use its products, and that the miscalculation would cost the industry, and the world, greatly.

“The horror, the horror,” said Shervin Pishevar, a venture capitalist at the firm Sherpa Capital who, like just about every leading light in tech, had strongly supported Hillary Clinton’s candidacy. “We didn’t do enough,” he added. “There were too many people in the tech industry who were complacent. They waited and waited and waited to get engaged in this election. And now we have this nightmare.”

Others were more succinct in their devastation. “I’m heartbroken,” said Stewart Butterfield, co-founder of the corporate messaging service Slack.