Is there any empirical evidence to back this up? If we’re talking anecdote, I swear as soon as google started labeling ads more clearly people complained more about ads. And if google really is getting worse, I would expect that I would get frustrated with DuckDuckGo bit getting the job done less often.
I do share your concerns though. Just look at YouTube as an example. You search for something, and half way down the page are completely unrelated videos that you watched before. This is because YouTube just wants you to click, they don’t care about you finding what you were after.