Earlier quoted context omitted.
The actual sponsored links end up at the top anyway. I don't see how bad regular results would contribute to their revenue; it would just drive people away.
>I don't see how bad regular results would contribute to their revenue Let's say you run a good song-lyrics site that has the correct lyrics for everyone's favorite songs. You happen to be on page 2 of google results for common queries; all of page 1 is taken up by spammers, fake pages, etc. How can you possibly drive traffic to your site? Maybe you can invest in SEO but no promises there. You'd be competing against…
And it all works together to make Google worse.
I agree that it would work as long as Google has an absolute monopoly on search. Google wouldn't care how bad their search results are, because there's nowhere else to go. But if there are alternatives, users should stop using Google and use the alternatives instead, and then Google has an incentive to improve their search results for users again.