I wonder if there isn't another factor at play, which is a death knell.

People using the internet have become so annoyed at intrusive ads and clickbait that they:
1) don't even see the ads, as if they were in their visual blindspot
2) purposely refuse to visit or click on ANY ad, even for a product that is accurately targetted to them.

Up until 2 weeks ago, browser adblockers did a great job of blocking ads on Youtube. Both ads that were fed inline with the video and thumbnail ads. I literally did not know what my wife was complaining about on her tablet, since I was not seeing ANY ads on my desktop computer. I didn't know what people were complaining about when they talked about 2 minute unskippable ads showing up in the middle of a concert video, intruding in the flow of the music or play.

Then Youtube changed something and now nothing blocks ads.

Several years ago I vowed to never click on an ad, even if it was for something that I was interested in. If I was interested in the product I opened a new window and went directly to the company's site.