The problem is, that in many cases, the amount of ads is higher than the amount of usable content in a video, even without counting the in-video ads (by the content creator). This is also true for many "normal" websites, where (especially some news sites) almost literally beg you to turn adblock off, since they cannot write content without it, and you naively do so once, to be bombarded by 50 different autoplaying ads, popups, overlays, banners, ads that move while you scroll, ads that break content into many small pieces, etc., forcing you to turn the adblock off, or with no alternative, to just close the page, because it's unusable.