Maybe it is the best we can currently do and maybe it isn't objectively great. But the real question: is it better? I mean, better than the random shotgun approach that was TV, magazines, bus wraps, billboards, etc. Is it better than the spam flyers or "yellow pages" the post office delivered to every single household in some geographic area?
Rather than compare to some idealized perfect, we should compare to the practical alternatives. Maybe this is legitimately the best we can currently do given the state of AI and machine learning. If that is the case, the right question for both advertisers and consumers is whether or not it beats the available alternatives. Because if it does, and advertisers seem to think it does, then that explains why Google and Facebook are worth what they are worth and how they can afford to pay what they pay.