The complete package. Hardware, software and ecosystem by a single company. Only Microsoft and Google have anything coming close to this.
Most organisations do not use MS or Google hardware though.
MS can provide everything for a standard office desktop, but the real strength of their OS is the availability of lots of third party software.
What exactly does Windows have that makes it easier to manage machines?
A large marketing budget and sysadmin / devops outreach in a way that no single and all Linux distributions collectively haven't matched. Integration of things into a cohesive single tool instead of a grab bag of tools that move from hyped to normal to unmaintained in a number of years.
KDE is also an obviously more "professional"/"serious" desktop environment that just makes it easy to open the tools to do work without a bunch of crap to turn off and without pointless UI churn requiring people to relearn how to use it. As far as bugs go, Windows IME has to be rebooted around 80% of the time after sleeping because either the WSL driver crashes or the VPN enters a permanently locked up state. I've had the start menu just stop responding to clicks when everything else is working normally. The thing is wonky as hell, and usually needs to be rebooted via the "hold power for 10s" method (do normal people even know about that?). I never run into issues on Linux (Fedora or Nixos).
The UI is also trash. e.g. if you type "reboot" or "restart" in the start menu (a common need, per above), it doesn't find the command you obviously want to run (KDE does for both), and it hides the (unlabeled pictograph) button you'd need to click to find it, requiring you to close the menu and re-open it. Nothing is organized anymore, so you need to rely on search, but search doesn't even work.
All of the Linux management tools are good, but they do not integrate as tightly with the OS and there are several competing ones. Microsoft has one tool and one thing to learn and that's it.
I say this as someone who has managed a fleet of Linux systems and whose current work is 100% Linux based. If a company can throw a smaller amount of money at something then they'll do it
Linux: I require a higher skilled admin who knows how to architect and build things
Because Linux has been built by developers for developers, it eschews braindead administration as a feature, because that's not something its dev community ever required.
That's changed somewhat in the past 15 years, but still lags Windows substantially.
Server-side, it's almost all Linux
If some genius hasn't already put together a turnkey umbrella project that meets your needs, you're going to have to find your own genius. That's different than just calling MS or Apple, even if their support is slow or annoying. I think Oracle counts, too.
It's not like Europe couldn't build these systems out of FOSS (just like Oracle and others, btw), they just haven't done it until now and it would have been just as easy to do 15 years ago. I think they'd rather get courted and bribed by American behemoths.
I'm an embedded firmware dev, so admittedly I am dealing with an entirely different list of vendors and asking for different things than the typical sysadmin or devops type.
With that said, it has certainly not been my experience that "having someone to call" actually solves my problems all that often. It's occasionally a nice to have, but normally I am reluctant to even start the process because my experience has been that it is usually a net drain on my time and energy to do so.
At this point, I am far more concerned with having access to source code so that I have a fighting chance of creating a workaround for myself, and failing that I don't want to contact my vendor so much as I want to replace them.
It might often have low practical value, but usually high CYA value.
That said, I love apple. Nothing else works like their hardware. It's not the best by a long shot, but I'm still able to use a mac-pro 8 years on. And my iphone is 7 years old (for me) and I got it used.