“So Google does outperform Bing (the difference is statistically significant), although it’s interesting to see the places where Google returns worse results.”
250 raters rated their own real searches, and Google still beat Bing. The study comes from a data labeling company, and its pitch for human raters sits in the middle of the method section. Google is better than Bing. That is a low bar, and nobody measured whether Google is worse than it used to be.