This has been done before multiple times and the resulting technical work significantly improved GNU (ECGS and EGLIBC come to mind). Also, historically, GNU maintainers aren't obligated to give total deference to RMS (the glibc steering committee comes to mind). So while "RMS is the king" might be true on paper, it's been neither true nor helpful to GNU in practice, and insisting on it simply hurts projects that are less well-staffed to fight political fights or organize forks. It doesn't help the free software movement at all.