Let's look at it this way - AT&T has invested the money for GB fiber to the home, with a presumed ROI attached. Part of that ROI is knowing either they will make money selling targeted ads, or they will make money by having you opt out.
Let's say enough people become untrackable, and it affects the targeting of the ads they are selling. Do you really think they are going to just sit back and allow themselves to miss their ROI target? What are you smoking?
The fact is, if you play with their targeting, it will lower their advertising rates, leading to less income to pay off the investment, and they will simply have to generate that money some other way...likely by raising prices of both privacy and basic service.
Now, about this plan of yours...where is the GOOD part? (And I know I will be downvoted...but honestly, did you think this through?)
OH - you didn't think of that one, did you?