> He wrote most of the LISP machine code.

That's nonsense. The Lisp Machine code was written by several people, some which had significant contributions.

Indeed. Before they left to found Symbolics, David Moon, Howard Cannon, Dan Weinreb, and others (I'm sure I'm forgetting at least one name) wrote the vast bulk of the system. I think Richard Greenblatt wrote most of the microcode (he also did most of the hardware design and construction).

After Symbolics formed, RMS did an amazing job at reimplementing many of the new features Moon and company were adding, so as to keep the MIT version of the system at rough parity with the Symbolics version. So his name belongs in the story, but not first.

The MIT version was commercialized, too. Lisp Machine Inc. employed Stallman and Greenblatt, and was back primarily by Texas Instruments.

Both Lisp Machines Inc. and Symbolics were selling the MIT version before redesigning it into their own brand new products, the LMI-LAMBDA and the Symbolics 3600.

The other side of the argument.

https://danluu.com/symbolics-lisp-machines/

Also interesting bits about the fall of Symbolics, the AI winter, and why Lisp adoption waned as a result.

If that's the case, then why is Emacs such a poor facsimile of the LispM environments? ;-)