I think you're arguing for the sake of argument here. Targeting people who have obvious self-selected and data-driven interests in what you're selling is going

I think you're arguing for the sake of argument here. Targeting people who have obvious self-selected and data-driven interests in what you're selling is going to do better than generic ads with no specific audience. This is practically science at this point. However nothing is guaranteed and a specific campaign not providing results doesn't have anything to do with the concept of targeted advertising.