... Then, if a developer is not willing to learn Gerrit, its code is probably not worth the effort of us integrating github/gerrit. That will just add some more poor quality code to your review queues.
That seems like a pretty big assumption, and likely to be wrong. The simpler the code review process, the happier people will be to submit patches. Quality seems independent from that, and more likely linked to the ease of validating patches (linting, unit test requirements, good style guides, etc). But that's just a guess. If deemed interesting, I would be glad to help quantify patch quality and analyze what helps to improve it.