Stallman likely worked in the LISP your describing. He was a researched at MIT's AI lab. Their the LISP machines they went on to produce were actually a hybrid natively assembled OOP LISP, aimed at solving a lot of the low level issues you'll run into writing a kernel/system tools in LISP. I haven't worked in this language, I've just seen it referenced in a large number of places.

As he ultimately decided to not go this direction, I'm going to assume he considered it more of a dead end.