These articles explain the demise of Symbolics: https://danluu.com/symbolics-lisp-machines/ https://danluu.com/symbolics-lisp-machines/ http://web.mit.edu/6.9

These articles explain the demise of Symbolics: https://danluu.com/symbolics-lisp-machines/ https://danluu.com/symbolics-lisp-machines/ http://web.mit.edu/6.933/www/Symbolics.pdf http://web.mit.edu/6.933/www/Symbolics.pdf Some of the reasons given were unique to Symbolics, others more general. LMI went under earlier, and the other two Lisp machine manufacturers (TI and Xerox) stopped manufacturing them but they had other products.