Take Fedora, Manjaro or Ubuntu with any major flavour like Gnome or KDE and you get a very consistent way of how your OS works and responds to common tasks. It's kinda easy for non experienced user to find the right settings with no UI change on a modern Linux Desktop.
You could build thousands of KDE environments with the amount of money MS spends on Windows, yet KDE has managed to update everything across 5 versions of their desktop environment. In fact, EVERY common operating system GUI with the exception of Windows manages to update all the things.
If MS had spent some of those billions on updating those legacy apps each generation, they wouldn't be stuck with so much legacy garbage today. It's also telling that MS has never bothered to stick with a framework that would allow them to upgrade UI themes in-place. I'd also note that "complexity" isn't a good reason because MS could have gone with other solutions that were both more simple and more usable, but chose a convoluted design instead.
It may be possible to provide an updated UI while still allowing the existing APIs and applications to work and integrate with the control panel, but it is not straightforward.
But KDE apps all look consistent. I don't really use it, but it seems to me that Gnome apps also are consistent. Ditto for XFCE.
Whereas Windows, even among out-of-the-box and "system" applications, there's a variety in the look & feel. Until 7 it was more or less the same. But starting with 10, it all went downhill, and 11 didn't really fix anything in that department.
For Windows, I don't think anyone complains about the fact that if you run an ancient Windows app, it looks like an ancient Windows app. In fact, backward compatibility has always been one of Microsoft strongest selling points. What people complain about is that Windows itself is inconsistent. Windows branded components, made and owned by Microsoft, included in the main OS with no alternative offered are inconsistent. The worst part is the control panel, it is a mess and they have no excuse, it is an unfinished job that shouldn't have been out of beta.
Arch packages do very little extra usually, and often works more like if you install from source. So it's not always the fault of devs, and is why installing from source was/is a thing.
Bonus with Arch is Aur, one big repo with most open source software available from git.
Additionally Windows is raking in MONEY for their OS.
So from that perspective, Microsoft have no excuse for the shitty software they make people endure.
Only if you intentionally ignore all the billions big-tech has poured into Linux over the years.
AFAIK IBM, SUSE, Red-HAt and Canonical are heavily investing in Gnome while other companies are investing in KDE.
KDE/Gnome aren't just some guys in a garage developing them in their spare time.
So dozens of huge companies, hundreds of smaller companies, they can all contribute code to an OS that is on-par with Windows, but missing things like patents and gaming hardware support that Microsoft pays for.
While Microsoft with all their advantages, all their insights and cooperations with hardware vendors still can't deliver.
It's really pathetic, and I put it down to their company culture not having any common goal.
What didn't they deliver? Last time I check Windoze desktop/laptop market share is still way higher than Linux despite Windoze costing $100 bucks and Linux being free.
And it's not difficult to see why. It's not even about the gaming anymore. The bugginess and jank of the modern Linux desktop can drive you up the walls.
For example, whenever I plug in my 4k monitor in my Ubuntu ThinkPad it rarely detects the 60Hz refresh rate, most of the time defaulting to 30Hz with no way of switching to 60Hz unless I go through a ritual of repeatedly unplugging and plugging the display-port cable again and again until the stars align and at the fifth or sixth time it finally detects the 60Hz option. Absolute madness that's a huge productivity killer. The Ubuntu 10.00 I used in university in 2010 - 2011 gave me less headaches than this. Yes, I tried different display-port cables. Meanwhile on Windows 10 and 11, both have always defaulted to 60Hz on this monitor and several laptops in the 3 years I had it, 100% of the time, every single time.
Now, since I need to get work/leisure done, and I don't have time to dig through Linux forums and tinker with the driver config files on Linux to find out why Ubuntu sucks so bad at detecting the right refresh rate, so windows has saved my sanity since the candy crush icon in the start menu is a lot quicker and easier to remove than having an OS that plays Russians roulette with your display refresh rate every time I start my day.