Well most of the arguments are the same, Richard Gabriel is just less tactful than pg.
What I want to know is whether Richard P. Gabriel ever had business success with LISP rather than just academic success. A quick scan of wikipedia doesn't mention any modern businesses.
He raised by my count over 4 million dollars back in the 80s (back when that was real money), and the company lasted 10 years. If that isn't getting a business "off the ground", I think your criteria is far too harsh!
But (if I understand the timeline) by the time he wrote that, the prior business had been dead and buried for 7 or 8 years. Reading between the lines, I think they attached themselves to a platform that looked good (symbolics) at the time, but which failed to capitalise on it's potential. Essentially they were in the accessories aftermarket... and if that market disappears you'll go down with it.
Lucid was the disruptive competitor to Symbolics: rather than building expensive hardware to run Lisp fast, they built expensive software to make mainstream hardware (e.g. SPARCs) run Lisp fast. AFAIK they never had a product that ran on LispMs.
What I want to know is whether Richard P. Gabriel ever had business success with LISP rather than just academic success. A quick scan of wikipedia doesn't mention any modern businesses.