This kind of reminds me of the mass surveillance debate. Without transparency we can't know for sure if targeted ads are worth the billions being invested. Empirically I'd be inclined to believe they do effectively pair users with ads they want to see. We create bubbles around ourselves, and because I have trained myself to engage very little with the ads they probably do not get any better at swaying me for a product. Most of us grew up at the start with shitty ads that can't serve us. I bet they they work well against people who don't safeguard their interests.

But I don't know.