For more than three decades, Martin Sorrell built WPP into the world’s largest advertising holding company by mastering the economics of the big creative campaign. Today, from the helm of his newer, nimbler venture S4 Capital, he is delivering a stark verdict: that blueprint is obsolete.

Over the course of a wide-ranging conversation about AI, Sorrell, one of the industry’s most closely watched figures, sketches out a future in which the billable hour vanishes, creative headcounts shrink and algorithms dictate where the world’s US$1.2 trillion in media spend flows. The shift, he argues, is not incremental but foundational, touching every corner of the business from the studio to the boardroom.

The first casualty of AI, in Sorrell’s view, will be the industry’s traditional pricing model. “Many of the big holding companies like Publicis, WPP and Omnicom are getting 25 to 40 per cent of their revenue from traditional creative materials, like copywriting and visualisation,” he says. “The time required to generate these materials is being severely reduced, and clients are aware of this.”

What once took weeks and cost tens of thousands of dollars – factoring in planning, briefs and multiple rounds of amendments – can now be drafted, visualised and iterated in hours at a fraction of the cost. Yet many legacy firms continue to bill on those old time frames. Sorrell calls this disconnect unsustainable.

“The agency model has to switch from time and materials, to unit‑based, output‑based or subscription‑based pricing,” he insists. The human consequences will be equally momentous: “You’re going to see fewer strategists and fewer creative people … There will be fewer of them, more highly paid, sort of an upper funnel based on strategic and creative capability, but it’ll be slimmer than it’s been in the past.”

A second front opens in personalisation. Sorrell describes the coming wave as “the Netflix model on steroids”, a reference to the streaming platform’s ability to spin a single show into thousands of tailored promotional assets for different micro-audiences. “Historically, we would produce for a Squid Game or a Narcos campaign maybe a million or a million‑and‑a‑half assets,” he says. “We can now do many multiples of that.”

If true, the changes to the industry will be striking. Creative production will shrink in headcount, while new kinds of talent will be required to manage, curate and quality‑control an explosion of AI‑generated material.