> Operating systems of that era were designed based on UX research
Too many developers nowadays don't know this. On any HN discussion of UIs, I've been noticing a growing number of younger devs insisting that usability is entirely subjective (their words, not mine). It's not just that they don't know about cleverly thought-out things such as safe triangles in nested menus or all the affordances/signifiers espoused by Don Norman et al. The bigger problem is that they don't know what they don't know, and they come across as being unwilling to learn.
It does make UX discussions frustrating and meaningless when they could, and should, be interesting and a learning experience for us all.
> safe triangles in nested menus
I did not know about this, but I did notice my own menu-rage every time a submenu disappears!
I was trying to use Orca Slicer (which itself is intractable) and it had a combo button whose menu was disconnected from the button. The menu would disappear as soon as the cursor left the button boundary, but because it was disconnected, there was no way to get to the menu without leaving the button boundary, traveling a void, and then getting to the menu. I’m unsure what incantation allowed me to finally choose the right command, but forget how it looks, it was if no one even tried to see if it works.
There are still UX research. It's just that the collective "we" has changed and we can/may build on some existing design decisions.
You are always designing something with a target audience in mind, and the next, e.g. mobile phone will very likely be used by someone who has interacted briefly with a similar device, so you may re-use some already learnt patterns.
The very early UXs built heavily on desktop metaphors (like folders), but at this point many (and an increasing number of) people are more familiar with OS UI n-1 than a typical office setting.
So I don't think jumping to this conclusion is correct - there are well-designed software, it has just become much much cheaper to create new ones, so the average quality has necessarily went down.