Elementary example: the likes of us will get requests from our tech-illiterate friends and relatives - "my internet is broken. It's really slow." And we will install ABP/ublock whatever.
This is, of course, assuming that there are no dramatic 'interruptions' - eg, browsers ceasing to support ABP-type extensions, the ads-versus-adblockers arms race moving decisively in the former's favour; etc.
I can't find any numbers on adblocker usage over time during the recent period - would be a good thing to look at - but here's the google trend, FWIW. https://www.google.com/trends/explore#q=ad%20blocker&cmpt=q&...