You are right, but the number of ad-block users is significant now -- around 20% (accd. to the same PageFair report).
I have also personally seen around 30% users use ad-blockers, for a site with around 100,000 visitors a day. However, most of the audience for that site is people in twenties, so it's not surprising to see higher than average ad-blocker usage.
[1] https://pagefair.com/blog/2016/mobile-adblocking-report/