Earlier quoted context omitted.
It's as simple as "if ads didn't work, YouTube, Facebook, Google, et al wouldn't exist"
If ads would have actually worked as preached by the industry, ad blockers wouldn't exist. ;) But it's Google's and Facebook's best interest to make people believe that they do, no matter the reality. What they actually do is increase sales by some measurable margin (not always great, but not zero either), while causing all sorts of negative effects (spam, scam, misinformation, all those "influencers" and "engagement…
I agree with that, but precisely because of how effective they are on manipulating people into consuming and wasting their time.