When I forget to sign in to YouTube, I see the same pattern, shitty ads that are clearly only allowed because otherwise YouTube wouldn't have sufficient ad inventory to meet their internal KPIs.
what about iPhones? They're ubiquitous enough that Apple probably doesn't need ads to let people know they exist, yet every at launch ads for them are plastered everywhere. Same with soft drinks and cars, just to name a few. Before you say "iPhone sucks", the same can be said for basically all other phone OEMs, and if your theory allows categorizing an entire industry as crap, your theory is basically unfalsifiable.
Or maybe, just maybe, the entire industry is crap and so many people are complicit such that it becomes a self-sustaining problem.