Why did UI's turn from practical to form over function?
E.g. Office 2003 vs Microsoft 365
It's easy to remember where everything is with a toolbar and menu bar, which allows access to any option in one click and hold move.
Seriously? Big ribbon and massive padding wasting space, as well as the ribbon being clunky to use.
Why did this happen?
You are immune to logic sadly, but I'll answer two things, which can be extrapolated to all you've said.
No, it all won't work fine at your work where you send documents and spreadsheets and stuff with complex functionality to your colleagues and clients. And they send their documents to you. And versions edited in your old version or LO break.
That aside, WordPerfect 8 doesn't support MSW document formats, IIRC, and MSW doesn't support WP8 document formats.
This is factually incorrect and I have already said it's incorrect. That research has mostly been exhausted, and the conclusions one can make from it are more or less the same as in 40s, 60s and 80s. And 90s' interfaces were more usable because by habit people tried to follow industrial ergonomics, even though computer displays allow one to cheaply shoot their user in the foot, in the way some device's panel with switches, buttons and knobs doesn't.
Some of it. But IBM and Apple had human interface guidelines based on actual research about ergonomics, which hasn't become obsolete despite what you say, because humans did not change as a race in 30 years. UI\UX following those is still good.
Judging by the first quote, you simply haven't done work requiring heavy usage of productivity software yet.
Also you are arguing like a schoolboy. Exactly in the way schoolboys consider to not look like it. I could give advice, but that usually only results in resistance.
If you can't engage with someone like an adult, don't bother talking to them at all.
yOu aRE a ScHoOlBoY iMmUnE tO LoGiC. Grow up.
I'll be here if you wish to further this without huffy remarks and silly playground insults.