I know I would certainly develop some defense mechanisms to justify working for a scourge like Google or Facebook, and they would probably assume a similar form to your argumentation here.
To anyone that grew up on the Internet in the 90s (I believe you are old enough to be in that group, correct me if wrong), the striking degradation of what was then a high SnR knowledge repository and a medium for rapid information exchange, should be more than obvious. The rise of surveillance capitalism can not be defended with appeals to highly-polarised what-ifs. The Internet is a platform for decentralized expression and emergence of new ideas. Your alternative futures don't seem to take that into account. I suggest a shift and widening of your thinking into what is possible rather than regurgitating the same old narrowing perspectives that your corporate masters try to enforce on us all.
It's not just adblock that's the threat: overzealous bans against tracking cookies have the potential to do much the same thing. Either way, ad revenue collapses, sites either die or switch to paywalls, and the internet becomes a much smaller, higher-friction, and lower-utility place. It'll be sad.
In a decade or two, the same people who today decry ads and tracking today will be the ones who pine for the open internet of their youth.