Edit: Writing PostScript and having no discernible security probably didn't make NeWS a great fit for the world of the Internet - but it was a lot of fun.
But Linux took over the world and it had a crappy UI. I was there, back when Xorg didn't even exist, running X and messing with modelines on Linux. All the window manager sucked big times.
Sun, just like SGI, got attacked by cheap beige PCs running either Windows or Linux.
I don't think their UI had much to do with their downfall and, arguably, SGI's UIs were better than the competition and they still disappeared too.
Also weren't most machines sold by Sun servers anyway? Their famous "We the dot in .com" tagline.
Linux took over the world because any licensing model that requires a per CPU license simply can’t work in a massively scalable situation like server farms and cloud.
Linux took over in all the places where a good GUI didn't matter. In ran most of the Unix server software on hardware orders of magnitude cheaper than what was needed to run a commercial Unix. Windows ran on that same cheap hardware but was much more expensive for the same capability.
Despite Sun's marketing push Linux was really the dot in most of the dotcom darlings.
like smartphones ;-)
FWIW and for good reasons current Android UI is terrible for a desktop usage and ChromeOS is too limited for some people.
Minix existed at the time too, I know because I ran it on an 8088 PC.
But within a few years, linux started gaining mindshare and was starting to replace proprietary unix especially on individual PCs.
It wasn't until mid 1992 that distros started to exist, and I'd say it took a bit of time for those to be complete enough to be usable for someone with a goal other than smoke-testing the kernel on their PC.
I can say for certain that I, a complete newbie, was able to boot SLS Linux floppies in early 1993, and within a couple months I was installing Slackware to HDD.
You also had SuSE, which really started as German-localized Slackware.
Somewhere, I still have a Red Hat 5 retail CD. I'm not sure, but I might have bought it at Borders Books rather than a computer shop. I know I bought a few CD-ROM collections at the bookstore.
The exceptions were mostly hardware graphics accelerators in some labs, when my Linux PC had to do it in software. And I got myself a surplus DEC Multia (alpha) that was really fast with Linux for natively compiled code, beating my contemporary 486DX3-100. But, the PC was still faster for web browsing, because running Netscape on alpha meant doing x86 emulation!
Likewise, my ~90 MHz Pentium MMX laptop with Linux was faster at regular dev work on my work-supplied Sun Ultra workstation in the late 90s. (Edit: Hmm, I am not sure about this laptop anymore, it might have been 166 MHz??)
Due to my positive experiences, I was an aggressive early adopter (and frequent beta tester) of nearly every Linux ecosystem frontier for decades. E.g. 2D accelerators, 3D accelerators, SMP, large file support, gigabit ethernet, wireless ethernet, power management, virtualization, 64 bit architectures, SCSI/SATA/Firewire/e-SATA/NVME, hardware and MD-RAID, ext2/ext3/xfs/btrfs, ...
My first exposure to Solaris was in 2003 when Linux had Gnome 2.6 and Solaris had CDE. The UI on my Debian box seemed decades ahead of the Solaris machines I managed, which looked like Windows 3.1 and performed about as well.
Combined with Linux package managers being infinitely better, the GNU core utilities having so many more conveniences and options than the Solaris equivalents, I felt like Sun was this dinosaur that couldn’t die fast enough. I’ll still never understand why so many people praise Sun for its engineering culture when free software seemed so superior to me at the time.
My favorite anecdote exemplifying my opinion about Solaris at the time: you log into the console of your Sun workstation, running SunOS, with your Sun keyboard plugged in, and press backspace. It echoes ^H back to you. They couldn’t even figure out how to configure their own keyboards correctly out of the box.
Maybe in the 90s the standards were different. Maybe their tech was better. But by the time I ever used their software is was the butt of jokes.
Sun got by because they had faster and more reliable hardware than what was available in the x86 space at the time. eBay's services ran on a handful of 64 CPU Starfire servers. And proprietary UNIX workstations had a bunch of specialized apps that weren't available on Linux at that point.
That's really an old-school UNIX convention that should have died with the move from teletypes to CRT terminals. The default behavior was that ERASE was # and KILL was @ (rather than backspace and Ctrl-C). It was typical for these to get set properly on logging in.
KILL isn't Ctrl-C. That's INTR, as you can verify in stty -a. KILL is Ctrl-U.
One of the other students in that class gave me a Mandrake Linux cd (It ran KDE) he taught me how to use SSH. After that I worked from home and submitted my assignments remotely. I have not looked back from Linux since.
I don't think it was limited to Sun. The first job I had out of university there were computers running HPUX also had CDE gave me flashbacks straight back to university. It definitely gave me the impression that all the commercial Unix companies were ancient Dinosaurs that had zero taste.
Linux having better UI than proprietary Unices (except SGI) was true from the beginning. In 01993, even before package managers, the Linux standard was color rxvt, color ls, Seyon, fvwm with multiple virtual desktops (really important at 800×600), Emacs preinstalled, and you could termify your web browser and whatnot so you could run them at home on a dialup shell account. Proprietary Unices (except SGI) had monochrome xterm, vi (with no arrow key support), and typically either twm or mwm, which both looked like shit and still do. Suns sometimes had olwm but Sun had sort of abandoned Open Look by that point. If you had a Sun at home connected through a dialup shell account, you could forget about running any TCP/IP apps on your Sun. By 01996 the Linux world had slirp, so you didn't even have to termify your TCP/IP apps, while Solaris didn't even include a C compiler anymore.
CDE seems like somebody thought that the problem with Motif was that, although it was butt-ugly, it wasn't quite ugly enough.
And, yeah, backspace worked. Also automatic window resizing. And for years Solaris had a totally fatal TCP round-trip estimation bug which made TCP connections to Solaris machines over dialup incredibly slow. Linux was just dramatically more technically competent.
Sun did have a pretty amazing engineering culture. They shipped SPARC, Open Look, NeWS, Java, HotJava, HotSpot, NFS, Sun RPC, yp/NIS, Spring, ZFS, OpenBoot/Open Firmware, and I think even Sprite, and for a while they employed the Tcl team, bringing Tcl out of the stone age. But they sucked at fixing the fatal flaws in their actual products, and half the engineering achievements in my list above were murdered by Sun's incompetent management.
Then Intel came out with dual-core processors, which was the new hotness. So he wrote a followup page, literally titled "Pecked To Death By Ducks With Two Bills".
At the time, I thought they were funny, and made reasonable arguments. But in retrospect, they were just trying to distract the customers from the fact that Intel was overtaking them.
Linux won on the server side because they got just as right as Unix. The crappy UI (windows) was the one that didn't work with shell scripting, didn't work with ssh, etc.
Once you have git and actions, I don't think that the language really matters all that much.
That wasn't even true back then.
What everybody except Steve Jobs got wrong was not taking user interface seriously enough. Not even Xerox. I've used aa Xerox Alto, a Sun workstation, an LMI CADR, and a Symbolics 3600, and none of them were as carefully crafted as a Macintosh with a tiny memory and a floppy disk. Next inherited this ethic.
Jobs valued the person using the machine more than anything else about the machine.