As you alluded to, many Chromium forks (notable exception is Ungoogled) are backed by tech companies. There's already plenty of intentional changes they maintain in their forks, like Privacy Sandbox,[0] so I don't think preserving support for v2 is a large hurdle for them.
Yup, this kind of criticism happens all the time. It's good to point out -- but a lot of people treat it like a deal-killer, which is the height of naivete.
Google described Manifest V2 as significant tech debt with new bugs still found there. Either they are lying or it's a non-trivial feature set to continue to support.
So will be interesting to see how many other browsers actually do keep this support alive.
A trillion dollar company? Lying? That's beyond the pale. Google has never done anything against my interests. They're always sooooooo honest in their communications.
[0]: https://support.brave.app/hc/en-us/articles/10742158329613-W...