IMO that's part of what they have to calculate for relevant. I'm also extremely thrifty and browse sites like slickdeals before I buy anything.

An AI with my search history should pretty easily be able to tell "Okay he just made a big purchase for a $2,000 GPU so he isn't going to be spending much again for a while.

Instead, what about some super cheap stuff that he might need instead. He searched for 'how to unfreeze windshield wipers from windshield in ice' so maybe an advertisement for 35% off a set of windshield wipers for his car which is model XYZ will be enticing?"

IMO that's the main power of an AI ad engine. It should be able to use common sense and make a personality profile for what I'm actually likely to care about, and then budget it for me. It should also know who's extremely thrifty and won't buy without a discount, and offer you a reason to actually buy it