Well, given that Sun workstations started running commercial Lisps at some "reasonable speed" around this time, that pretty much doomed Symbolics/LMI/TI's efforts. The cost differential between the specialized hardware (ca $100K) and the commodity workstations (ca $10-20K) was just too much.
When you think about it at another level, there's not enough difference between a decent Lisp compiler producing 68K instructions for the Lisp primivites on the Sun workstation, and the microcode in the Lisp machine running micro-instructions implementing Lisp primitives. So the commodity hardware won out, as it usually does.
When you think about it at another level, there's not enough difference between a decent Lisp compiler producing 68K instructions for the Lisp primivites on the Sun workstation, and the microcode in the Lisp machine running micro-instructions implementing Lisp primitives. So the commodity hardware won out, as it usually does.