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?
It's not UI backsliding. It's Microsoft being incompetent. I have no idea how they're still in business, and astounded at their valuation. It seems like everything they manage to push out is just barely functioning
Moving away from Office and Windows and so forth is a nightmare for any larger company. If you use specialized software, it might very well only run on Windows or only have an integration into Office. Even if you could, you then have to retrain staff to use Libre Office, Linux and other alternatives. You also will have problems converting, changing servers and so forth.
So companies just do not switch. That is how Microsoft makes money. They really do not care that much about private users. That is only usefull so people can use their products.