Does this number includes mobile browsers? Given the big mobile browsers do not have adblockers (or even extensions altogether?), that would explain it.
I don't use uBlock. But I learned how to write chrome extensions and it turned out extremely easy to insert my own CSS and JS snippets to the selected pages. So I just added few URL filters to remove most obnoxious tracking and ads, I added very few CSS edits to the selected websites to remove popups and I added some JS to youtube to remove its ads. Web is pretty fast and usable for me. I did not cut every ad, but I don't often browse new websites and I'm okay with some ads as long as they're not very bad.
The reason I don't use uBlock is because I think that it's overkill for me to run thousands of filters for every website in the world. And also I like the fact that I'm in control of my user agent. For example recently I turned off feature on some website which paused video when I switched to another tab. I did not like that feature, so I disabled corresponding JS handler, simple as that.
I don't use an ad blocker - I feel bad since ad revenue is the only thing most of these sites have (OTOH, I don't run ads on my own blog because I don't like what the ad-supported internet has become).
Almost all of them I assume? Browser ad blocking is much less widespread than people seem to think, otherwise there wouldn't be so many ~trillion dollar companies built around tracking and advertising on the internet.
i wonder if the the fact that the most popular ad-tech company also producing the most popular mobile os has something to do with it.