RMS had pretty much left both the LISP machine and the DEC MAINFRAME (TOPS20 and ITS) by the time he got around to creating EMACS, he started GNU because he wanted a new super system and he figured starting with UNIX which he regarded (if you read the manifesto) as incredibly deficient.   The idea was to come up with a  new UNIX-ish kernel with all the crap he had come accustomed to on the LISP machines and iTS.   Of course, he got run over by LINUX along the way.