Forking Chrome is useless, Google can just take a bunch more of engineers to work on it, add some features to chrome, and extinguish your project again.
Forking Chrome would be like fighting against Embrace, Extend, Extinguish after you’ve already lost (which we have with Chrome, compared to what KHTML used to be like)
That's true of any large open source project, whether heavily backed by a company or not. You need both users and developers to make a fork successful.
Regardless, though, there's nothing that says the hypothetical developers of a Chromium fork couldn't devote some time to merging reasonable fixes & new features from upstream.
Google may discourage forks, but there's nothing they can do to prevent one, and forking Chromium is no more difficult than forking any other project its size.
... or any contribution that doesn’t fit their ideals.
That's one of an OSS project maintainer's more important jobs. I used to maintain some decent-sized open source projects, and part of my job was to say "no" when someone wanted to add something I didn't think belonged (for whatever reason).