what consumers had access to by walking into a retail computer dealership ... and saying "give me your best"
Of course, by that metric, Suns weren't available at all.
SCSI was somewhat rare in a PC in 1992, yes, but not that uncommon. (Anybody remember the Adaptec AHA-1542B? It came out in 1990.)
800x600 was more common, but 1024x768 was available. I don't recall if it was all interlaced or not, but I do recall how much that interlacing sucked!
Ethernet (or token ring, that was still somewhat common) was quite common in environments where it made sense. Not in a one computer home of course, but in a business, sure. How else were you going to get at the NetWare server?
And in the PC space, the higher-end you went, the less you were able to actually use the hardware for anything typical.
That's not true. A high end business class PC would run games just fine in 1992, for example. (As long as it had the right graphics, anyways.)
You might need to pick a different boot floppy, however. (Windows 95 certainly did improve things there!)
I'm not sure if this applied to the few SMP PCs available the time or not, however -- I got my first one a few years later, a Pentium Pro. That wasn't specialized -- it would run anything, though I imagine that many things would ignore the second cpu. (I ran Linux on it, which did use the second cpu.)
The UNIX platforms were standardized around SCSI, ethernet, big memory access, high-resolution graphics, and multiprocessing and presented an integrated environment in which a regular developer with a readily available compiler could take advantage of it all without particularly unusual or exotic (for that space) tactics.
I understand nostalgia, but ... no.
SCSI was the (somewhat) new hotness in 1992, yes, but other drive busses had been used in the past and were still used in 1992. The large SGI I administered a few years later had ESDI drives, for example. (But it also had SCSI, and the desktop SGIs we had were SCSI only.)
Ethernet was also the current favorite, but other networking protocols were in use at the time. I was working at IBM in 1992 and most of the company used token ring at the time -- that's what I had coming to my desk, where I had a PS/2 running OS/2.
As for "big memory", yes, that was always the norm for big computers, whatever the OS -- big computers had big resources available.
As for multiprocessors, remember, the Sparcstation 10 was Sun's first multi cpu desktop box. Multiprocessing was somewhat common in mainframes and minicomputers by them (whatever the OS), but it was rare on the desktop, even *nix desktops.
As for graphics ... most Unix platforms had no graphics at all then. Sun's desktop offerings did, and they did have decent graphics, but they weren't really better than high end PCs that were available at the time. (SGI went more after the desktop graphics than Sun did, but maybe Sun had some stronger offerings that I'm not aware of.)
As for "integrated environments", I think in 1992 Sun still shipped compilers stock with their OSes, but it was just a few years later that they became a very expensive licensed add-on. gcc was available, of course, but getting it installed was kind of a chore, and it was inferior to the Sun compilers in some ways. Alas, g77 wasn't available until a while later.
And really, the environment wasn't "integrated" like it is now. No IDEs, anyways -- your environment was X windows, and you got to use vi or emacs or whatever. Really, the programming environments on a PC were integrated before they were on Unix systems as far as I know.