If a) would be the case, they most of the time would know it and if b) would be the case, I would have seen it too and thus a).
Examples: I use Canon and Fuji gear for taking pictures, but they offer me Nikon or Sony related videos. If they would actually have some interest to optimize suggestions, they would offer me to say "I'm not interested in Nikon/Sony/whatever" … wouldn't they?
Or Amazon, offering me Sony lenses for my Fuji. Or more of Thing-X after buying some Thing-X yesterday. But I only need exactly one new Thing-X, which their stupid "AI" Rufus should know by now if their suggestion machinery didn't know it already ;-0
I aggressively nuke channels instead, and use a ublock script to hide anything with a red bar (which means I previously watched it).
Tangentially related, I typically queue multiple videos, and within the past year YouTube has started inserting new videos into my queue. It’s always one by the same person of the currently playing video, placed next in the queue, and it only gets inserted after watching the current video for some period of time.
That last part made it difficult to diagnose. It’s extremely annoying and feels like gaslighting because it’s never a video I actually have an interest in watching.
Has anyone found a way to disable this?
But it gets so much worse. I leave the "smart downloads" feature enabled in Youtube Music on my phone because sometimes it discovers and downloads some gems for me. Again and again it downloads "artists" and music genres that I went out of my way to never have to listen to. To add insult to injury it sometimes refuses to delete those playlists for hours after I click the button. One time I had to clear all the downloads just to remove that trash.
There is no "organic" explanation for this as much as I'd dig for one. This is Youtube taking money to push a product.