You may be right that Google and others technically offer
some tracking opt-out capability (mostly because they were required to by GDPR), but it doesn’t seem to work, because
I still regularly receive targeted ads (relating to recent web activity):... Despite having painstakingly turned off every available tracking switch from every service I’ve ever signed up to.
... Despite no longer using any services from Google, Facebook, and many others (except when I must via a link from someone else).
... Despite using privacy oriented browsers with all privacy features turned on.
There are so many problems with the current “opt out” model:
1. They do not make it easy to find all these switches. (And it seems intentional, though I can’t prove it.) In addition to there being no global “off” switch, they nest countless switches behind deep hierarchical navigation graphs, where it is extremely difficult for a human to reach every node without missing some.
2. Even when you find the switch, it’s not always clear which choice is the “most off” position, and some switches do not have a “fully off” position.
3. Many switches use extortion to convince you to keep them on: For example, sometimes you’ll be shut entirely out of a service for turning off a tracking switch with dubious explanations as to why they can’t operate the service without it.
4. Many switches will automatically and silently turn back on if you so much as visit the wrong link to their service. Sometimes this happens silently, and sometimes it happens via confusing “dark pattern” prompts.
5. Google isn’t the only one. You have to repeat this whole process for every other service you use (if they even have the switches available).
6. Despite all this, you’ll still be tracked by trackers that don’t need or want you to have an account with them.
The last item can perhaps be summed up by the fact that I still get very targeted ads for things I’ve been searching for on DuckDuckGo even despite all these efforts. Clearly trackers are still embedded into various endpoint web pages and are figuring out what I’m doing despite it all.
It’s an interesting experiment to try yourself: try to actually not be tracked via a regular or even fairly privacy oriented browser.
As far as I can tell, aside from getting into something like Tor, it really can’t be done: If companies can track you, they will. And they can. So they do.