I'm not saying that there aren't content producers who want that or would benefit from it. I'm saying that they probably won't make as much money that way. And if the only way to do it is to use pervasive tracking and digital surveillance (which users are increasingly blocking and lawmakers are becoming skeptical about) then it's a business model on unstable ground to begin with.
My experience, especially with media content producers, is that those ad platforms are never sufficient and it's always advisable to rely on partnerships or Patreon. Because, yeah, it's more work to create those relationships, but the alternative is relying on a low-revenue platform where a small update from the whims of Google might destroy you without warning.
My understanding of your argument is that no publisher should be using Adsense etc today, and they should all be negotiating direct deals instead, is that right? What would you say to publishers (and I've talked to many) who are happy to have the "collect bids from people who want to advertise on my site" portion automated for them so they can focus on running their sites?
(Still speaking only for myself)