My Symbolics systems are elegant, don’t get me wrong. But Genera wouldn’t have been any less elegant if they’d taken their 80386+DOS deployment environment (CLOE) and used it as the basis for a true 80386 port of Genera. They were too stuck on being better than everyone else at designing hardware for Lisp that they missed not needing special hardware for it.
Actually I think Lucid was founded, because Symbolics did not want to further invest into a UNIX based implementation. Symbolics did support SUNs with Lisp Machine boards (the UX400 and UX1200). TI had Lisp Machines with UNIX boards.
Later Symbolics developed a virtual Lisp Machine running Open Genera (a version of their Genera operating system) for the 64bit DEC Alpha chip on top of UNIX.
"The Symbolics Virtual Lisp Machine Or Using The Dec Alpha As A Programmable Micro-engine"
They wouldn’t even let a company decommissioning a workstation give it to an employee who wanted to take it home without paying about the cost of a Macintosh in “license transfer fees” and then whoever got it had to pay “maintenance” to stay within the letter of the license.
VLM is decent but they’d have been better off retargeting 80386 and 80486 atop either Unix or Windows, rather than trying to maintain their own special fancy architecture forever.
To do a bit of an apples to apples comparison, look at the Apollo and Sun workstation lines versus the Symbolics workstation line from 1983/4-1991/2. That takes you from the Apollo DN300, SUN-1, and Symbolics 3600, through the Apollo DN10000, Sun SPARCstation 2, and Symbolics XL1200. They all started at about 1 MIPS but ended at very different positions.
The Symbolics system is only available as a pirated and slighty buggy software for Linux (also in VM running Linux). A better version exists, but that one is only available in limited commercial form. It's another parallel universe from 30 years ago. Most development basically stopped mid 90s.
They will also give you that answer, for various reasons.
Instead of sharing one minicomputer having 8 MB RAM (or less) with tens or hundred users, the Lisp programmer had a Lisp Machine as a first personal workstation with GUI (1981 saw the first commercial Lisp Machine systems, before SUN, Lisa, Macs, etc.) - thus the Lisp programmer had not to compete with many other users with scarce memory availability. Often Lisp programmers had to work at night when they had a minicomputer alone - a global garbage collection would make the whole machine busy and response times for other users were impacted, up to making machines unusable for longer periods of time. When I was a student I got 30 minutes (!) CPU time for a half year course on a minicomputer (DEC10, later VAX11/780).
So for a Lisp programmer their personal Lisp Machine was much faster than what he/she had before (a Lisp on a time-shared minicomputer). That was initially an investment of around $100k per programmer seat then.
Later clever garbage collection systems were developed, which enabled Lisp Machines to practically use large amounts of virtual memory. For example: 40 MB physical RAM and 400 MB virtual memory. This enabled the development of large applications. Already in the early 80s, the Lisp Machine operating systems was in the range of one million lines of object-oriented Lisp code.
The memory overhead of a garbage collected system increased prices compared to other machines, since RAM and disks were very expensive in the 80s.
A typical Unix Lisp system was getting cheap fast, though the performance of the Lisp application might have been slower. Note that there is a huge difference between the speed of small code (a drawing routine) and whole Lisp applications (a CAD system). Running a large Lisp-based CAD system (like ICAD) at some point in time was both cheaper and faster on Unix than a Lisp Machine. But that was not initially, since the Unix machines usually had no (or only a primitive) integration of the garbage collector with the virtual memory system. Customers at that time were then already moving to Unix machines. New Lisp projects were also moving to Unix machines. For example the Crash Bandicoot games were developed on SGIs with Allegro Common Lisp. Earlier some game contents was even developed on Symbolics Lisp Machines - the software later was moved to SGIs and even later to PCs. Still a UNIX based system like a SUN could cost $10k for the Lisp license and $40k for a machine with some memory. Often users later bought additional memory to get 32MB or even 64MB. I had a Mac IIfx with 32MB RAM and Macintosh Common Lisp - my Symbolics Lisp Machine board for the Mac had 48MB RAM with 40bits and 8bit ECC.
Currently a Lisp Machine emulator on a M1 Mac is roughly 1000 times faster than the hardware from 1990 which had a few MIPS (million instructions per second). The CPU of a Lisp Machine then was as fast as a 40Mhz 68040. New processor generations had then either been under development, but potential customers moved away - especially as the AI winter caused an implosion of a key market: AI software.
For an article about this topic see: http://pt.withington.org/publications/LispM.html
"The Lisp Machine: Noble Experiment Or Fabulous Failure?"