I have noticed this on YouTube as well, I would assume something similar is happening on other video sites.
Sometimes there is a video on a trending topic among the first few Google search results, and when you go over to YouTube and have a look it turns out to be a montage of stock and/or stolen photos, with a synthesized voice reading a narration that was obviously churned out by a content mill somewhere very low-wage, if not generated by "AI."
It baffles me that Google ranks these things highly, it's not like they don't have an eye on YouTube activity.
In the end I have no better explanation than institutional rot: so much money is flowing in, and engineering incentives are so perverse, any problem that doesn't directly irritate the cash cow is not gonna get fixed.