To many tech-industry watchers, the time is nearing when AI becomes so pervasive that companies start going out of business.Photographer: Ying Tang/NurPhoto/Getty ImagesArtificial intelligence’s imprint on US financial markets is unmistakable. Nvidia Corp. is the most valuable company in the world at nearly $4.5 trillion. Startups from OpenAI to Anthropic have raised tens of billions of dollars. But there’s a downside to the new technology that investors are increasingly taking note of: It threa...