At the risk of stating the obvious: We've ample evidence for this insidious effect with ~25 years of Google changes, as clear ads become hidden ads, separation becomes deliberate clutter, and actionable results get degraded into interaction-bait.

Not the source I wanted to recall/find, but a timeline with screenshots:

https://www.howtogeek.com/how-google-search-results-have-cha...

Kind of ironic that an article that criticizes Google turning into an ad machine opens up with a “we have noticed you have an ad blocker installed” whole page pop-up