> So what happens when publishers and advertisers start seeing less and less return? They stop spending money on Google ads, don’t they?

I think the assumption is that they won't, because they have no alternative.

> the “presence of an AI Overview now correlates with a 58% lower average clickthrough rate for the top-ranking page.”

I think most of the article points out real problems, but this seems a bit synthetic. From what I can tell, the "AI Overview" usually appears in the top spot, but some portion of the time (A/B testing? predicted quality based?) it appears in the second spot, after the top-ranking page. Assuming a significant number of users (myself included) instinctively scroll past the slop to see the real results, this will lead to a bias towards increased clickthrough for the second-ranking page, at the cost of the top-ranking page, because the top-ranking page is now put where they're training users not to look.