I think the only time Google still reliably gives better results than Duckduckgo is for non-English languges (which Qwant is good for), or when Google has something indexed and Bing/DDG does not.

But taking it as a given the Google's results are better, is that really because of lack of privacy, or just because of how Google has been pouring more money and talent into the problem longer than anyone else? Because I'm not convinced that personal data is particularly useful for generating search results. The example they always give is determining whether a search for "jaguar" means the cat or the car. But that always seemed silly to me, because most searches are going to give extra context to disambiguate ("jaguar habitat"), and even they don't, the user is smart enough to type "jaguar car" if they're not getting the right results. Further, Google doesn't actually know whether I'm more interested in cars or cats—it justs know that I'm a woman in college, so it guesses that I'm less interested in cars. Is that really so useful?

Does searching Google through Tor give noticeably worse results than searching google while logged in? I would be genuinely surprised if it did.