Google is the biggest of browser and http/s internet based protocol, so much bigger that everyone plays by googles rules. if they set out manifestv3 the other browsers that are not compatible will not work, and as a result people will abandon them.

Google gave up WEI, for now at least. They will try again later though. https://securityboulevard.com/2023/11/google-wei-is-dead-richixbw/

It’s because he just regurgitates all his takes from /g/ on 4chan.