Not really, but it is kind of obvious. I have a very weird setup which would be quite easy to fingerprint (probably a handful in the world and likely only one in my town uses my display setup for one). I am the only one using my devices and noone else is using my IP (and I don't switch IPs either) and I don't use any ad-blockers. Yet ad networks haven't got a clue, often even get gender wrong. (And as a male i interested in tech that should probably be the easiest scenario imaginable)

I guess the most tangible data point is when google allowed you to look at what google thought if you (gender, age, interests etc.) and how bad they are at it unless you actually use their services.

It is obvious they would be far better of targeting sites than users without accounts. But that is not where their competitive edge is so they downplay that. Also, I guess they are big enough to not care about people without accounts.