The digital advertising landscape will add over $400 billion by the end of the decade. But beneath this impressive growth lies a more complex story of market share battles, emerging platforms, and rapid consumer behavior changes that challenge conventional wisdom about where the industry is headed.
"Marketing's history is littered with cautionary tales, examples of well-intentioned decisions that backfire despite being grounded in good data," said our analyst Sarah Marzano at EMARKETER's Ad Buyer Strategies Summit keynote. Her presentation used EMARKETER's latest forecast findings to examine how competition, structure, and pressure points are evolving in ways that top-line numbers alone don't reveal.
While the "big three" platforms, Amazon, Google, and Meta, will continue capturing nearly three-quarters of digital ad spend, Marzano said significant shifts are occurring within that seemingly stable dominance.
The established platforms are no longer operating in their own silos, Marzano said. Instead, they're aggressively pursuing one another's core revenue streams.
Meta is building tools to move closer to the path to purchase, aiming to capture more lower-funnel spend traditionally dominated by retail media. Google is similarly targeting retail media to maintain relevance as commerce-driven budgets flow directly to retailer platforms. Amazon is moving in a different direction entirely, developing capabilities to capture product intent even for items it doesn't sell directly, with ambitions to become the starting point for all product search.
These strategic moves are producing measurable results. Marzano said Google will lose 10 percentage points of market share by the end of the forecast period, Amazon will gain six points of share, and Meta will capture an additional 2.5 points.
"These are meaningful shifts, particularly if you evaluate them against the context of the rapidly expanding market," she said. "We start to see just how effectively retailers have become at monetizing the consumer intent that exists on their platforms, offering advertisers a compelling opportunity to influence consumers in the environments where they're making purchase decisions. The ecosystem beyond the Tripoli continues to grow into an increasingly unignorable force."
In 2026, Google's share of total search ad revenue will dip below 50% for the first time, EMARKETER forecasts, with retailers and their media networks capturing the lion's share of those gains.
This inflection point demonstrates how effectively retailers have monetized consumer intent on their platforms, Marzano said. They're offering advertisers the ability to influence consumers in the environments where purchase decisions actually happen, a compelling value proposition that's pulling dollars away from traditional search.
"You have players ranging from retail media networks to last mile delivery, social platforms and streaming services, but what makes this extra interesting is how the makeup of this cohort is changing over time as well," she said. "Between 2024 and 2028 the number of platforms in this category that will capture more than 1% of ad spend share will increase from 19 to 24 leaving advertisers with an equally complex landscape to navigate that features a growing number of platforms they simply can't afford to ignore."
This fragmentation creates both opportunity and operational challenges for brands trying to maintain effective reach.
ChatGPT moved from the 20th most-visited website globally to number five in less than two years, according to SimilarWeb data. That puts it ahead of Amazon and X, in the same neighborhood as Meta's family of apps, and within striking distance of Google.
This unprecedented pace of consumer adoption is reflected across EMARKETER's AI-related forecasts:
The comparison to social commerce is particularly striking. What took social commerce well over a decade to accomplish in terms of scale and volume, AI-driven ecommerce is expected to achieve in a fraction of the time.
"[This] is a pace of consumer adoption like we haven't seen before, which leaves platforms and advertisers left with limited time to react and determine how to respond," said Marzano.
Despite the impressive growth trajectories, AI-influenced commerce and social commerce remain tiny fractions of total retail spend, Marzano said. When viewed in the context of the entire retail industry, the distance between technical capability and what consumers actually do becomes clear.
Marzano pointed to the "collapse of the purchase funnel" narrative as an example of hype outpacing reality. With the exception of TikTok Shop, every major initiative from upper and mid-funnel platforms to shorten the distance between discovery and conversion has failed and been sunset by the platform.
"What retailers provide via a really complicated combination of inventory, curation, fulfillment, logistics, trust, branding and loyalty to create the credibility and trust necessary for consumers to make a purchase is harder to emulate than maybe we gave them credit for," she said.
Technical capability doesn't dictate consumer behavior. Understanding how consumers actually behave in different environments, whether they're seeking entertainment, discovery, or ready to purchase, remains critical for effective advertising strategy.
This was originally featured in the EMARKETER Daily newsletter. For more marketing insights, statistics, and trends, subscribe here.
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