OpenAI CEO Sam Altman has weighed in on remote work and is not a fan, saying, “the experiment on that is over.”

Remote work has been a divisive topic since the onset of the pandemic, with companies large and small turning to it to stay operational amid lockdowns. Many companies doubled down, committing to remote work long-term, while others were eager to get back to the office.

According to Fortune, Altman was speaking to attendees at a Stripe-sponsored “fireside chat” in San Francisco.

“I think definitely one of the tech industry’s worst mistakes in a long time was that everybody could go full remote forever, and startups didn’t need to be together in person and, you know, there was going to be no loss of creativity,” he told attendees. “I would say that the experiment on that is over, and the technology is not yet good enough that people can be full remote forever, particularly on startups.”

Remote work is increasingly falling out of favor, with even ardent supports reversing course. The trend is significant that it is even impacting where Americans are choosing to live, with many returning to cities.