I agree that relevant ads are better than completely random ones for everyone involved. But there is a significant middle ground between “show this user a random ad” and “show this user an ad based on data collected through tracking”. There’s also “show this user an ad similar to what they’re currently looking at”, like the search ads on DuckDuckGo. I find that these kinds of ads are just as relevant as targeted ads. The big disadvantage compared to using tracking is the inability for advertisers to select demographics directly (instead, they would have to choose pages or search terms to appear near).