Regulating AI may be a prevalent topic at the highest levels of government and tech, but the moment to get it right may have already passed.

“Regulation is going to have to be self-regulation,” said Sir Martin Sorrell, founder and executive chairman of S4 Capital, this week at the Fortune Global Forum in Riyadh. “The cat is out of the bag. We’ve missed the Oppenheimer moment. Many people compare it to the control of nuclear weapons.”

Sorrell—famed as the founder of advertising giant WPP—went on to explain that tech companies and individual figures like Elon Musk are simply too rich and influential for governments to meaningfully bring down a regulatory hammer.

“Apple’s at $4 trillion, and Musk’s compensation in his latest plan is geared to a $10 trillion valuation,” Sorrell told the audience. “I have no doubt that Musk or Tesla will get to that valuation. At some point, we’ll have a $10 trillion company. To put that into perspective, other than the United States and China, a $10 trillion company would effectively be the third-biggest [economy in the world]. They’re nation-states. The ability of governments to control them, I think, has become limited.”

In some sense, we’re already halfway to Sorrell’s prediction: This week, Nvidia became the first $5 trillion company in history. The chipmaking behemoth’s shares shot up in the aftermath of comments from President Donald Trump about meeting with Nvidia CEO Jensen Huang.

Looking ahead, Sorrell also foresees that, especially in advertising, we’re soon set to see audiences lean into and accept “the use of synthetic people … imaginary people in advertising.”

“Our view is that over the next two to three years that will become commonplace,” he said. “The reason is economics. We’re talking about a huge disruption. You’re talking about reductions of as much as 80% to 90% of production costs, out the window, and taking create costs down—whilst media costs and creating more money for media investment will become more and more important.”