The only reason why a mediocre ads company like Google is managing to mess up the web is that it has >90% of the browser's market share, if you include all Chromium-based browsers.
If they can periodically break the basic functionalities of web extensions however they like (HTTP calls within extensions, background scripts, ability to manipulate the DOM...) just to ensure that people won't manage to block ads and trackers, and they still get developers to build stuff for their browser and they don't lose a single user, they can really get away with EVERYTHING.
Time to let them know that they can't really get away with everything. Google has been an evil company beyond redemption and with a net negative added value to the industry for too long and now it deserves to go down. MV3 should be the reason why developers should stop building extensions for Chrome, users should stop using Chrome, and other browsers should move to other web engines than Chromium.
If nobody follows Google in their efforts to push for MV3, then we'll be left with a limited browser with limited functionalities and nearly no extensions. Let Google sink in their own sh*t.