What I find interesting is that google/youtube doesn't circumvent adblockers, though they easily could, given that they own the whole ad supply chain. For example, they could make the ads indistinguishable from the actual video (in the html), or even splice the videos into one stream. My guess is they don't because a) they are wildly profitable anyway, and b) they don't want to alienate adblock users, especially the techies.