They got people who have to fight in internal politics to get something in and nobody with clear vision steering the ship. They need to fight for that to not get their funding cut so they're highly motivated and would need a wrangler, a captain.
They can't agree how the start would open up from the side so you need to patch 11 to get a movable taskbar etc, the default start is seen(fought for) just as an advertisement space for user attention.
Underneath things have gotten better all along mostly, but the ui layer is dominated by bozos who don't understand that you could configure windows 3.1 into "night mode" if one wanted, that you could theme windows 2k to look like beos etc. It does not need to be one size fits all users.
I bet the designers don't even use windows.
Further examples are that you still do actually need the old control panel and thats why its still there.
This rot affects all applications outside of windows itself as well where design refreshes done for no reason at all often omit features of the previous design.
Back when windows phone was relevant their developer ambassador had the gall to say "you don't need that feature" when asked when a feature would be available we had to have to port that companys app i was working for. Said ambassadors presentation btw was doing simplest game you can think of.. By using ui widgets. If you asked him how to display arbitrary pixels he wouldn't have known. But they gave us a bunch of devices and food etc still, complete waste of time and use of money in the wrong things.
Another good example of this is copilot. They had cortana already, but for some reason need this new branding and the reason is just internal funding funnels. They also push it to be used without figuring it out what for. They already had desktop widgets ages ago but need new branding for that too. They force enable lock screen widgets because then they get user statistics that show they're being used but frankly i don't want them. Whats most ridiculous is that they don't explain where you would get lockscreen widgets that you might actually care about! How about a rss ticker? No can't have that have to reinvent something because the designers don't know what that even means.
Osx isn't much better, but a bit better in this sense - have you lately tried to find screensavers that still actually work for osx? Good luck with that.
(Anyway if you need to use win11 "explorer patcher" is the patch to get a movable taskbar, o&o shutup is easiest app to turn off a bunch of stuff and openshell makes the start button behave however you want)