Similar result, maybe not quite so illustrative, perhaps more colorful, just involving images not videos. Ended up at a similar conclusion.
Tried to search user interface design for an ongoing project, and found that Google now simply ignores filtering attempts... Try to find ideas about multi-color designs, and all there is are endless image spam sites and Letterman style Top 10 lists. Try to filter those out, and Google just ignores many attempts.
There's so many, that even those that actually do get successfully filtered out, only reveal the next layer of slime to dig through. Maybe the people that didn't pay enough for placement?
Huge majority, far and away, where the "Alamy", "Shutterstock", "_____Stock", ect... photos websites. There's so many it's not really practical to notch filter. Anything involving images. Spend all day just trying to notch filter through "_____Stock" results to get to something real.
The worst though, was that even among sites that wrote something, there was almost nothing that was actually "user interfaces" or anything related to design, other than simplistic sites like "top 10 colors for your next design" that are easy to churn out.
Try to search on a different subject and filter for only recent results from 2024, get results from 2015, 2016. Difficult to tell if the subject had simply collapsed in the intervening 10 years (seemed unlikely) or if Google was completely ignoring the filters applied. The results did not substantially change. It's like existing in an echo chamber where you're shown what you're supposed to view. It all feels very 1984 lately.
Basically ended up at the same conclusion: their customers are the ad buyers. They don't get enough money from "normal" people to care.