FYI your cutoff idea is what Google actually does. Ad quality is a problem Google works on. The main complaint people have is that Google doesn't do a good enough job of overruling users "for their own good" when those users are consistently actively telling Google what they want to see.
If that were true, why would there be a need for Adblock? Google would just stop showing ads to people who don't like them, or would be showing us all such great stuff that we'd be grateful for them.
