Because many tech people who are sticks in the mud like this don't actually care about the browser, or the implications of what's happening in real time.

They'll eventually leave and wonder why nobody told them sooner.

Ugh, that's a bad analogy and you know it. No actually what you're doing is a classic case of "it's in the EULA, so they can do it". Like, if tomorrow Google puts a clause in their EULA that they have the right to harvest the eyeballs of everyone who lives on Earth, you'd be scrambling for passage to Mars. "It's in the EULA! Corporations are all-powerful and can do anything, as long as they state it in the EULA!"

I no more fear Google banning ad-blockers than I fear Toyota putting spikes on all of their steering wheels. It would be much more painful to their bottom-line than any Toyota drivers, because people would do this magical thing called... not using that product.