Independent measurement is becoming marketers’ best defense against a platform-driven ad market, according to new research projecting AI-influenced self-serve platforms will handle more than 80% of US ad spend by 2028, a shift already reaching radio sellers.
Globally, that same automation will touch more than 70% of ad spend by 2028, according to Gartner. The firm distinguishes this so-called “back-office” AI, which quietly shapes who sees an ad, what it costs and how it gets delivered, from the generative AI tools marketers use to build creative.
Gartner recommends CMOs concentrate investment on the platforms most critical to reaching priority audiences, curate a smaller set of additional platforms to test new opportunities, and favor partners that support transparency and outside evaluation over those that don’t.
Those same pressures are already taking hold in audio.
In May, Radio Ink reported that 82% of marketers and media agencies now buy audio programmatically, up from 65% a year earlier, with spend projected to reach $2.59 billion by the end of this year.
Futuri Media’s 2025 analysis of more than 20,000 AI-generated media mix models found radio receiving little to no share of recommended ad spend, with Anthropic’s Claude and Google’s Gemini excluding the medium in 100% of the plans tested. Futuri traced the gap to radio’s sparse, inconsistently formatted performance data, the exact kind of verifiable measurement Gartner now says CMOs will increasingly demand.
Yet audio’s overall share of ad spend continues to shrink even as automation grows. WPP Media’s year-end forecast, covered by Radio Ink in December, projected audio’s share of global ad spend falling from 4.48% in 2024 to just 3.08% by 2030.
Gartner VP Analyst Eric Schmitt said, “AI is not merely helping marketers execute campaigns faster. Advertising platforms are using it to exert greater influence over how marketers reach their audiences, what they pay, and the outcomes they achieve.”
Schmitt added, “AI was expected to make advertising more efficient, but improved platform economics does not necessarily translate into lower costs for the advertiser. CMOs need independent evidence that they’re getting the returns they expect. The more influence AI has over advertising decisions, the more important independent measurement becomes. CMOs need confidence that platform performance reflects real business impact, not just platform-reported results.”
