There are enough unsuccessful forks of GNU Emacs. None of them get enough attention and support for whatever reason, but I guess mainly because there have no real reason to exist. Emacs devs are working diligently and improving it regularly, and there is no good and simple solution for the problems it has.

There won't be any nvim/vim-like Schisma happen, unless some super-dev appears who can outsmart the whole community and it's devs. Maybe, in a decade when AI become good enough and someone feeds Emacs to electron or something like that.

> What Emacs needs is the nvim/vim Schisma.

It's already had like six, over the decades.

There was Xemacs back in the day… and I guess it is still around.

It's still around in the same sense that twm is still around.