Firefox has made a few headlines over the past year for privacy-unfriendly moves. That's the context you're missing, despite it being in some of the first sentences of the linked article.
Which is a UX issue, not a Web standards issue. None of the major forks were made due to a difference opinion about how the standards should be implemented, so they are all dependent on Mozilla to implement the standards.
I suppose, but I wouldn't try to predict the response to Firefox becoming unmaintained and interested parties who might step up to carry the torch before it actually happens. It's the primary browser of the largest three commercial Linux distros.
