The fact that the ad model has worked so well is always a nice reminder of how much of a bubble I live in. Personally I have never intentionally clicked on a Google/YouTube/etc ad. Never. I wonder if the general population has been getting more tech-savvy and skeptical of ads over time, but this change takes a very long time to play out. I sometimes see my dad clicking on ads because he doesn't understand the mechani…
I was in Google Ads 2008-10, and people from outside the company always said, "Oh, I never click on ads!" To which I responded, "Well, someone does, or we wouldn't have all this free food." There's a simple test of your hypothesis, which they can do easily inside Google but it's harder to do from outside: has CTR gone down over the years?
Maybe something like rate of change of CTR is stable relative to the rate of change of traffic.