Problem is, Google has a monopoly. Most people are using Chrome on Windows and won't even notice this unless they use an adblocker (or a tracker blocker, or anything alike).
The people that use an adblocker just wouldn't be able to access the websites that are blocking adblockers, installing Firefox won't help them unless Firefox also implements the DRM.
Google is trying to pull a Microsoft here (embrace, extend, extinguish)

CC: @lina@vt.social