No chance if done single-handedly or by a tiny group. I believe, most forks end up dead in some months (if ever synced with upstream). It's no big deal to fork

No chance if done single-handedly or by a tiny group. I believe, most forks end up dead in some months (if ever synced with upstream). It's no big deal to fork a project and write some code. Yet, it's requires a tremendous effort to maintain it and keep up with all the upstream changes. (I wonder if there's enough of community bothered by ever-increasing infestation of the browser by Mozilla's own proprietary technologies - e.g. anything related to "Firefox Account" - to start a schism.)