What actually happens is a cycle. Things rise, things fall, things die.
On the initial upswing things tend to get better while profit and growth are aggressively pursued. Once market dominance is achieved, things tend to get shitty thereafter until someone topples the stagnant product.
This is a legitimate opportunity for Linux + hardware partners, if someone can finally realize they need to build and market to average consumers, rather than expecting average consumers to skill-up / knowledge-up just to use their software.
But the terrible UI/UX? I guess they saw they had to entice users to move by changing the look and feel, but didn't give the programmers enough time, so it was mostly unfinished garbage when it was released, and maybe still is the case.
On that note, I have Win11 and Office version whatever at work. I really fucking hate new Outlook, it's a garbage web app, the whole "NEW" label on the icon makes me always think "Oh I've got some new emails. Oh no, it's just Microsoft being fuckwits". Also, the UI for modifying email signatures is a confusing maze of unfinished UI.
They do crap like UI mixing (old and new versions existing together) because backwards compatibility is what got them the marketshare they have in the enterprise (well that and anti-competitive practices). At some point, to improve their products, they are going to have to break compatibility and just push forward, and yet they can't because that would immediately alienate a significant portion of their enterprise customers that rely on that compatibility to run old software from vendors that no longer exist, that are critical to operating some niche equipment - hell, it's not uncommon for me to see air gapped windows XP machines still in production running some critical workload.
So they're stuck because they both simultaneously need to move forward but also can't break the old stuff without screwing over their customers.
98 good, ME - bad, XP good, Vista bad, 7 good, 8 bad, 10 good. Par for the course, and I wouldn't be surprised to see a bunch of refinement, and some changes rolled back for Windows 12.