It's true that Guile is a Scheme implementation, but it is also a platform to host any other language. The Guile-Emacs project wasn't about removing Elisp, it was about making Elisp run on the Guile VM.
Someday in the far far future long after Scheme is supported and millions of lines is rewritten in Scheme, I could imagine dropping support for Elisp.
Then Emacs will be nothing more than a large Scheme program that could run on any implementation of Scheme