Sir Martin Sorrell says advertising’s AI reckoning is really an efficiency reckoning

Spend an hour with Sir Martin Sorrell and advertising quickly becomes a proxy for the world economy.

When I met the S4 Capital founder and executive chairman at Sydney’s Park Hyatt last week, I had expected the conversation to begin with agency consolidation.

After all, the global holding companies are simplifying portfolios, merging brands, folding capabilities together and pushing clients toward more unified, platform-led operating models. In Australia, Dentsu’s move to shutter the Carat and iProspect brands has made that debate feel particularly immediate.

But Sorrell’s view moves faster and wider than the industry’s internal machinery.

For him, the agency sector’s current pressure is only one expression of a much larger shift: slower-growth and a more fragmented global economy in which marketers will have to be far more selective about geography, far more ruthless about efficiency and far more serious about AI.

“What is exciting is that the world is in a mess,” Sorrell says.

It was not a throwaway line. Sorrell, who built WPP from a small shell company into the world’s largest advertising and marketing services group before launching S4 Capital, has spent decades reading the agency business through the wider forces of capital, client pressure and global expansion.

SEE MORE: Dentsu folds Australian media brands into single agency model

His current read is blunt. The world is not returning to the era of “globalisation on steroids”. Instead, marketers are operating in a more fragmented global pattern where growth is harder to find, risk is more unevenly distributed and market selection matters more.

“I think we’re going into a phase where growth is slower,” Sorrell said.

“Inflation is going to be more stubborn than people think,” he added, arguing that central banks “never got it down to the 2% which was the long-term objective” and that interest rates will remain “higher than we’ve been used to”.

For marketers, that matters. Higher interest rates and stubborn inflation change consumer behaviour, squeeze discretionary spending and force businesses to defend margins. They also intensify the pressure on marketing departments to prove efficiency, not just growth.

“So, in that world, efficiency, the latest iteration of which is sort of blockchain AI and coming down the pipe is quantum computing, becomes even more important,” Sorrell said. "Those two things make the world, I think, a really interesting place."

That is where the AI debate becomes more interesting. Sorrell does not frame AI as a shiny technology layer sitting on top of marketing. He sees it as the latest and most powerful tool in a long-running shift that began with the internet, accelerated through data and digital media and is now reshaping the economics of agency work itself.

The result is a harder, more operational version of the AI story. Not simply faster content or cheaper production. But a structural reset in how marketing services are priced, delivered and measured.

“AI is affecting visualisation, personalisation at scale, media planning and general efficiency. Then there is the democratisation of knowledge,” Sorrell said.

Most significantly, he said it is changing agency revenue models from a time-and-materials basis to one built around outputs, usage and subscriptions.

“It’s changing the revenue model from a time and materials model to an output-based model,” he said. “We’re trying to get clients to pay on the basis of number of assets created and number of times used.”

An AI reckoning?

That shift goes to the heart of the agency business. For decades, the industry’s economic foundation was built around people, hours, teams and retainers. AI challenges that directly because it compresses production time, automates parts of media planning and creates a different basis for valuing work.

For CMOs, it creates a different kind of procurement conversation. Marketing departments may be attracted to speed, scale and lower cost. Procurement teams, Sorrell said, remain more conservative. But the direction is clear: as AI makes marketing outputs easier to produce and optimise, clients will increasingly question whether they should still pay for the old inputs.

This is also why Sorrell sees current agency consolidation through a sceptical lens. Merging agency brands or folding capabilities together may create cost savings, but it does not automatically create strategy.

More important, he says, are leadership, strategy and structure.

“The three dimensions: who’s the leader, what the strategy is and what’s the structure?” Sorrell said.

On that score, he argues Publicis has been the clearest among the major groups, with a strong leader in Arthur Sadoun, a clear story around data and digital and a country-first structure. By contrast, he questioned whether capability-led structures inside the holding companies risk creating internal divisions at the very moment clients want more integrated accountability.

The point is not academic. As marketers ask for fewer hand-offs and clearer access to capability, the agency groups are trying to simplify themselves. But Sorrell’s warning is that consolidation without strategic clarity can become a cost exercise dressed up as client benefit.

“Good people are good by definition, but good people who share are the real ones,” he said. “They’re the ones that you really want.”

If the agency model is under pressure, geography is also being re-priced.

Sorrell still sees the US as strong. South America has “enormous opportunity”. Africa has opportunity but remains too volatile for his taste. Asia remains central, but not without geopolitical risk. China, he argued, is too important to ignore but too risky to overweight beyond its share of global GDP, particularly given Taiwan.

India, however, stands out. “You could de-risk like India, which is the world’s fastest growing with superb leadership around Modi,” he said, also pointing to Vietnam and Indonesia as important growth markets.

New growth markets

By 2050, Sorrell expects Indonesia to sit among the world’s top five economies, alongside China, the US, India and Germany. Europe, by contrast, is where he sees the biggest structural challenge.

“Europe is where the problem is,” he said. “UK and France have got big problems, Germany’s got issues. So Europe is a structurally challenged part of the world.”

For Australian marketers, there is a lesson in that map. Growth strategy is no longer just about scale. It is about choosing markets with a sharper understanding of risk, demographics, geopolitics and local consumer momentum.

Australia, in Sorrell’s view, remains a stable market, but not a high-growth one.

“Australia is very steady,” he said, describing it as an oligopolistic market where share tends to switch between a small number of dominant players.

The opportunity for agencies like S4 Capital locally sits where traditional media declines and digital continues to grow. But even here, Sorrell’s broader view applies: the money follows digital, the pressure follows efficiency and the competitive advantage sits with those who can bring data, content and technology together faster.

He is particularly clear on the scale of digital’s dominance.

Internet advertising, he said, is now between US$900 billion and US$1.2 trillion globally and represents about 75% of the industry. By 2030, he expects that share to move closer to 80%. Traditional media, unless attached to live sport, is going backwards.

The next battleground is not whether digital wins. That fight is over. The next battleground is how effectively marketers use AI, first-party data and platform signals to make digital work harder.

Sorrell describes personalisation at scale as being based on two data sources: first-party data and signals from the platforms. His Netflix example is telling. The platform is already good at personalising recommendations, but he believes it could go further by using behavioural signals more effectively when viewers abandon content or show signs of dissatisfaction.

For CMOs, that is the practical AI challenge: not just creating more content, but building systems that learn, refine, optimise and adapt around customer behaviour.

The risk is that marketing does not own enough of that transformation.

When asked whether CMOs have a role to claim in AI as more companies appoint heads of AI reporting directly to CEOs, Sorrell was direct.

CMOs are in the position where they don’t have as much power as they used to.

That may be the most important point for marketing leaders. AI is not only a creative or media planning issue. It is an enterprise change-management issue, touching data infrastructure, content supply chains, customer experience, pricing, sales and procurement.

If CMOs do not shape that agenda, others will.

Sorrell said companies tend to change only when there is an external threat. In automotive, Chinese EV makers are forcing incumbents to move faster. In financial services, digital banks are applying pressure. In packaged goods, commodity prices and margin compression are making efficiency unavoidable.

“They only change when there’s an external sting behind it,” he said.

That sting is now arriving from multiple directions at once: slower growth, higher rates, procurement pressure, platform concentration, AI automation and new competitors with lower cost bases.

For the advertising industry, that means the AI reckoning is not just about technology alone, but rather efficiency and whether they can turn that efficiency into growth.

"Whether a holding company keeps one agency brand or folds it into another, the real question is whether the business has the leadership, strategy and structure to compete in the world now taking shape."

That question now applies just as much to CMOs as it does to the agency groups trying to serve them.