In this case the argument is focused on Apple forcing you into their ecosystem. Even though some packages might be generic, Xcode tools & codesign wont run and build on another OS then MacOS.
This is just like saying clang compiled for Linux won’t run on Windows [1].
[1]: Yes, I know about WSL. No, that doesn’t count.
It's not: for any other OS, you can develop and compile on whichever other OS you want. Sure, MSVC won't run on Linux, but you can just compile it with clang or GCC on Linux and target Windows. There is no way to do that for iOS.
And this is not because no one wants to write a backend to target iOS, it's because Apple won't allow it. If you want to run native code on iOS, it must be built and signed with XCode on a Mac.
Try to create a UWP application or Windows service, or do any kind of debugging or ETW monitoring, like that.
Fair enough with UWP. Might be one of the many reasons no one uses it...
I will still note that debugging and monitoring are usually not going to work cross-platform - try to log to journalfs from a Windows system (wihtout using MinGW or similar).
In Linux they would have been separate packages, but I don’t think the App Store has dependencies so how else are they going to get the required packages installed for their ide.