This seems fallacious. The whole reason for that "more expensive targeting cohort" becoming available after tracking is its increased relevance. Otherwise, everyone would be getting the $100 ad in the first place-- the $10 ad would simply be uncompetitive!
I'm not saying relevance is meaningless. I'm saying it's scaled by the profitability of a conversion as well. This business logic works on traditional non-targeted ads as well, like on broadcast TV.
For example, do you remember seeing ads along the lines of "if you or a loved one has been diagnosed with mesothelioma, call the law offices of such and so"? Mesothelioma affects less than 30 people per million. Why run an ad that so few people care about? Because the payoff is so high for reaching the people that do care, and the higher the payoff, the less people have to care for the ad campaign to be worthwhile.
