1990 was already 10 years after the first machines had some wider availability. 'Wider availability' means more then 20 hand-made machines and having commercial vendors (LMI and Symbolics, then TI and Xerox). Yeah, Lucid was pretty nice - too bad then went under when their investment into C++ killed them.

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"

http://pt.withington.org/publications/VLM.html

Lucid was founded because Symbolics was unbelievably expensive and unbelievably arrogant. “We will always be the best so you have no choice but to pay our prices, nobody can match our performance or technology.”

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.

Ironically we are still catching up with what Lucid was pushing for C++ when they pivoted.

Also, once the Symbolics 3600 series was released in the early 1980s, Symbolics looked like they were just resting on their laurels relative to the rest of the industry. There weren’t binary-compatible performance improvements every year or two like the rest of the workstation industry was seeing, it took the rest of the decade to achieve that kind of improvement, and with only source compatibility, in the form of the XL series.

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.

At the time custom hardware was much more common and was attractive, it would have needed rare foresight to bet on 386 a long time before x86 became attractive. Unix workstations, Amiga, etc were doing well and Intel hw was generally seen as pedestrian and stuffy with bad graphics, and 386 seemed like another attempt from intel to dig x86 out from the DOS hole (it broke compatibility with 286, OS/2 had targeted special 286 features...). 386 Unix vendors weren't doing that well either. NeXT Cube with 68040 was launched in 1990 and nobody knew intel was going to overtake Motorola. etc.

In fact, one of the "Lisp machine on a budget" options of the mid 80s was the Hummingboard -- a 386 with many megabytes of RAM on an ISA card, specifically commissioned and built to work with Golden Common Lisp.