Agentic AI's ROI problem: Publishers at Cannes demand proof, not hype

At the 2026 Cannes Lions festival, the rosé is still flowing but the mood among publishers has shifted markedly from the experimental AI enthusiasm of early 2025 to a hard-nosed focus on return on investment. This year’s gathering serves as a mid‑year checkpoint on two existential questions for the digital media sector: who will fund the open web in an AI‑dominated ecosystem, and whether agentic media buying is a genuine fix or merely a rebranded ad‑tech tax. WPP’s media arm set the tone by unveiling a video‑buying agent just before the Croisette opened, but many publishers arrived with a skeptical eye, determined to separate bluster from reality. Joshua Stinchcombe, global chief revenue officer at the Wall Street Journal, captured the shift: “This year, the AI conversation has completely shifted – moving past experimentation into real ROI.” He highlighted the new frontier of discoverability as consumers pivot to AI agents and chatbots for search, underlining that publishers need to be findable in these conversational interfaces. Yet the central tension revolves around agentic trading, which promises to automate media buying through AI-driven systems that negotiate and execute placements. While the holding groups tout the technology, publishers are asking tough questions about technical readiness, budgets, and whether these systems will genuinely reduce friction between buyers and sellers. One senior commercial lead at a major news group stated bluntly: “We are in Cannes to work out what’s bluster and what’s real.” The anxiety is palpable: will agentic setups dismantle the opaque intermediary layers that some publishers estimate swallow up to 50% of ad spend, or will they simply introduce a fresh set of fees under a trendy label? The historical context is critical. For years, programmatic advertising has suffered from a complex supply chain where multiple intermediaries each take a cut, starving publishers of revenue needed to produce quality journalism. Agentic buying could theoretically streamline this by letting AI negotiate directly, but without transparent design and data‑sharing protocols, it risks becoming the next must‑have label that justifies another fee layer. Publishers want clarity on how their data will be passed to these agents and whether the holding groups are prepared to trade in that manner at scale. Beyond the fee debate, there is a deeper concern about who sustains the open web. AI‑powered search and discovery are reshaping traffic flows; if consumers get answers directly from AI agents without clicking through to publisher sites, revenue models collapse. Cannes is thus a venue not just for dealmaking but for hashing out the architecture of a future where AI mediates access to information. The outcome will shape whether publishers can capture value or become mere data suppliers to technology platforms. The conversations at Cannes 2026 suggest the industry is moving past the hype cycle and into a period of rigorous evaluation, where proof of ROI will be the currency that separates lasting innovation from ephemeral buzz.