Gartner expects most advertising money to move through self-serve platforms where AI shapes buying, costs and outcomes by 2028. Eric Schmitt, a Gartner analyst, warns marketers against handing those systems too much control. He argues the platforms' AI serves the seller, not the buyer. Recommendations often amount to advising advertisers to spend more. Schmitt says a human should stay in the loop on budget decisions. He notes the platforms still do not measure or work well across each other. His advice is to cut the number of variables and focus on the largest platforms. He also suggests bringing finance colleagues into the assessment. Independent measurement providers should check campaign results rather than platform reporting. Junior staff can operate the consoles, but experienced oversight remains necessary.

• 70% of global ad spend via AI platforms by 2028
• 80% of US ad spend by 2028
• Google, Meta, Amazon: over half of US paid media