Even if you don't use the ads or if simply ignore them, you still represent a group of interests that can be used to feed and train the machine.
Google learns through the searches you make and through the videos you watch and your behaviour will be used to improve the accuracy of ads shown to other people. That's your payment for using Google's services.
The only reason people stop interacting with ads it's because ads don't bring any real value, And any data that Google might collect brings up that value a lot.
I think you underestimate a lot of the number of people unaware of Google's presence and influence when it comes to advertisement. This number is much bigger than the number of people who install adblock on their browser.