Until society determines that the practice is unacceptable and outlaws it. Outlawing it won't completely eliminate the practice, of course, but it would dramatically curtail it, and provide people with an actual means of rectifying the situation when someone is breaking the law.
All sorts of data is collected every day that is not monetized, but could be.
Consumers are allowing their data to be monetized by agreeing to sign up for "free" services which take an asset from the user which they do not know how to monetize themselves.
In a way the dynamic is similar to the early 20th century BP oil fields in Iran; the Persians had oil under their feet for centuries but outsiders came in and started to pump it out of the ground, making themselves rich but the general public of Iran - not so much. They didn't even know what to do with oil at first.
Once the Iranian people saw what was going on and realized that they were being exploited, they elected a leader who sought to nationalize the oil fields, since they finally began to understand what asset they had and how and why they could monetize it themselves.
The internet needs its own Mohammad Mosaddegh, so to speak. Not to commit property crimes and break contracts like Mosaddegh did - but to show the masses what is going on in a way that encourages them to change their behaviors in a fundamental way.
[EDIT] my point is there's a ton of info being collected that goes way beyond web server logging, so I don't know how this became about why all this is impossible because server logs are a thing.
"absolutely necessary" does not mean anything. For example, tracking in banking systems has very good justifications such as fraud detection. That alone means banks have a blank check to connect tons of features about their users, and not for nefarious purposes.
[EDIT] to your EDIT point: even with server logs you could start building user tracking and if your net is large enough you can derive a massive amount of data just from that. Pattern analysis, sites/services users connect to, geolocation, etc... even without the most sophisticated tracking systems this is already good enough to build business value.
"waaaah but we need to share it with 'partners'" hahaha OK whatever, but bet you don't though. Illegal. Figure it out. Bet you can.
You don't need to keep the data long-term (though it would be more profitable if you could). You can still get a lot of value using the data to train an ML model, then use that model to build valuable decision-making systems, which few other companies could produce.
Plus, banks training models for fraud detection has an obvious benefit to everyone.
I don't understand your point. If it can technically be done and it is valuable in any way, it WILL be done. No matter the justification.