Considering that the push for Guile is not coming from the Emacs community, but from the Guile community in order to promote Guile, I guess that Emacs will be forked as soon as they deprecate Elisp and start forcing people to use Scheme. Switching to Scheme will be GNU Emacs's suicide.
Let me ask you this:
If Emacs and all of its extension code was completely rewritten in Scheme, what would be the point of sticking with Elisp? And how would using a Scheme-only Emacs be "GNU Emacs's suicide"?
What concrete value does Elisp add over Scheme?
CL vs Scheme, I could see an (unconvincing to me) argument for, but Elisp? Elisp?
Don't get me wrong. I'd much rather use Elisp than most any other non-lispy language. I just don't see anything in it to recommend it over a modern Scheme like Guile.
But I'm open to being shown the errors of my ways. What's so great about Elisp? Please enlighten me.
Rather, I hope the switch is made gradually, and most of all that Elisp fans don't dig their heels in against it, but rather work to make the transition smoother.