UX I'm less sure about - I now use a 4K monitor to do a bunch of things I used to do quite successfully on 1024x768.
Performance of a bunch of basic apps has also taken a few hits here and there (at least in part due to that big resolution bump, and despite massive hardware improvements).
I definitely have some nostalgia for that era, but it's possibly more nostalgia for the age before the internet consumed all of computing...
Meanwhile, I was running IRIX (for which my record was 4 years without a reboot, and that only due to a power outage) and Linux; and when I got some money, macOS X: all rock solid.
edit: I just remembered that Netcraft used to have a server uptime leaderboard, and for quite a while in the 1990s, Lamborghini was at the top of the list with their IRIX servers. The earliest archive I can find of the list is from 2001, with ONLY FreeBSD and IRIX occupying the top 29 places: https://web.archive.org/web/20010226190549/http://uptime.net...
George RR Martin famously wrote on WordStar for DOS (a rewrite of the CP/M version) until at least 2014.
Turbo Pascal didn't have memory protection, but people still loved it and compare it favorably to modern IDEs. Both Turbo Pascal (DOS and CP/M) and Think C (Mac) have featured on HN repeatedly iirc.
As I understand it, Apple's Lisa had memory protection, but the Mac gave it up to reduce hardware and memory requirements. Apple's Pascal compilers (like many) supported range checking, but developers turned it off, giving up reliability for performance and code size. Then they switched to C, which laughs at memory safety* and introduced null pointers that conveniently pointed to Mac OS data in low memory/writable RAM (perhaps a hangover from Apple II/6502 programming.)
It's almost like CPU designers going for performance at any cost and introducing isolation and security flaws.
* Prof. Kernighan might point out that there are ANSI C compilers that are memory safe and that nobody uses, and that clang/LLVM might even implement a safe memory model someday
Tbh, it's all downhill from there, every new release gets a little worse not to mention all the hardware issues too.
Today, the Mac harangues you every time you wake it about the updates, then to apply them, you must reboot immediately, and stare at various Apple logos and progress bars for an indeterminate amount of time (no estimates offered).
The same is kind of true of retrocomputing. We look back to these old platforms as if due to coming from a "simpler time", they never had any latency and never experienced bugs. And sure, if you fire it up for five minutes on some online WebAssembly emulator you find on Hackernews, it seems much snappier and more pleasant to use than Windows 11. But back then, we were running them on CPUs literally hundreds of times slower than even a potato-class computer from today. And due to memory protection being frickin' absent from almost all consumer-grade operating systems, they crashed. A lot. Even the Amiga was crash- and Guru-Meditation-prone depending on what you were running on it. It was such an enormous relief for me, trying out Linux or even Windows NT for the first time, to watch the OS simply yeet out a misfiring app; disconnect any access it had to the network, file system, or window system; and proceed merrily on its way as if nothing happened. Not following the exact sequence of steps it required to set up the message pump properly so that your program can respond to messages as required in Windows 3.1, for instance, can cause strange glitches within Windows itself, requiring a restart of Windows; or even hard-lock the system requiring a cold boot.
Our computers are so powerful these days, and our software so sophisticated, that they've eliminated entire classes of problems from the old days, only to open the door to entirely new classes of problems (like adware that would have brought a Pentium II to its knees, and sparked a user complaint campaign that would have resulted in major egg on the vendor's face if not bankruptcy from the ensuing lawsuits, being routine, and even required, on commercial operating systems of today).
Offtopic, but here's how to feel old: More time has passed between the debut of the AVGN and the present, than has passed between the debut of the NES in the West and the debut of the AVGN.
"Very pretty but can't do much" was a general take on the Mac OS cube of the day.
The lack of a fan or any decent cooling, the "lack of a floppy disk" (for those of us who didn't use Zip drives), it was pretty to look at but hard to work with.
We had one to run FrameMaker on, but beyond type-setting (& fonts), it was a shiny thing which was treated like a sunday sports car.
Where I was, the Tex user group is what eventually materialized into a Linux User group and there was simultaneously love for the screen, rendering and fonts for the Mac, but near hatred at having to use it to professionally typeset things.
Math publications quickly jumped ship out of Adobe due to OS 9, but very few came back to the OS X versions until years later when Apple started making really good laptops with fast hardware.
The G4 Cube had an (empty) standard mount and power connector for an optional fan.
It was the 90s equivalent of a kernel panic - you'd get a dialog that basically went "the computer is about to explode. click here to restart"
At the ">" ROM debugger prompt, type the following lines, pressing Return after each:
SM 0 A9F4 G 0
:)