There are a couple of steps missing at the beginning. There was a time when we only blocked popups; other types of ad were fine, but popups were annoying enough that they needed special attention, and the popup-blocker was usually built-in to the browser without needing an extension. It took a couple of years for the non-popup types of ads to become obnoxious enough to warrant blocking.

Even better: system-wide DNS adblocking on Android. Get rid of in-app ads too.

My feeling of guilt when scummy megacorporations miss out on ad revenue:

😛