Goodbye FLoC, hello Topics

What would they sue over? You order ads to be shown to interested people, they show ads to interested people. And then you work out how you are going to pay for those ads: per click, per view, per click-conversion, or per view-conversion.

And if you pay per view-conversion, obviously the algorithm will optimize for that, resulting in this effect.
Even if ad networks wanted to, I doubt the AI could be trained to "maximize conversion rate, but by creating new purchases, not predicting them". (They would if they could, because customers will notice a 30% conversion rate with ad broker A resulting in higher sales than 30% with broker B.)