Also typical Lisp hacker won't buy a slightly edited and printed version of the HyperSpec or a printed version of the SBCL manual.
Add to that that Lisp made a deep dive after the AI winter and that they were sure to not sell enough copies. At that time it was also a good idea not to be connected to Lisp.
Plus, I guess they did not like Lisp. 'Clojure' has the 'advantage' not to use 'Lisp' in its name.
