As long as people don't abandon search, yeah, they do. If they lose their absolute dominance in search, they will automatically have competition on adsense too.

Or maybe Google disagrees with my assessment, but I can't imagine what kind of inside information would make them do that. It looks like a very clear and inescapable reality to me.

You should know that's not how capitalism works. They have to keep making more money per dollar every year or they get punished in the market. They've tapped out on their limits of growth and now actual costs are increasing due to floods of automated crap at levels far beyond what we had in the past.

They have a practical monopoly on web and mobile ads, if they really are stagnating then all they need to do is jack up prices by a fraction of a cent and it's already billions in profit. I'm sure they have no problem increasing revenue over time.

Given how stupidly common ads are, increasing prices and upping scarcity would be a good thing overall anyway.