Now ask in any privacy-focused community whether you should block Google Analytics and you'll almost certainly be laughed out for even considering that you should not.
Add to that that there is already an industry emerging around privacy. Many anti-virus programs already today ship with anti-tracking features. This industry is very much interested in telling their users about user tracking. And they won't give the fluff-explanation of "Yes, you are being tracked, but it's for your own good." like Google and friends are trying to establish.
Then make them care.
> track with ga and gtm
That is a far bigger problem than advertising. I'm fine with sites that track the pages they serve, because that is local only. The problem is when these per-site events are aggregated into a single database.
If someone has the event log of every website you visit, not only do they have your entire reading list, they also have a very accurate picture of your pattern-of-life. Google can probably estimate e.g. when you sleep or the length of your commute simply from the timestamps of the GA events they can correlate to your account.
I see your point, but realistically I don't think any organization could/would ever do this. Outside of NSA vs. Snowden type cases, but I guess that is where it really counts.