There are demographics where Apple has dominance.
M Pro series are probably the best laptops on the market, and if people keep buying them, is the price too much?
MacBook Air is actually quite well priced for what you get.
As such both Windows and MacOS are closed source.
As for “opening up the OS” both are pretty gosh darned flexible and extensible wrt other features.
However being based upon a BSD core, MacOS has had access to the Unix command line natively since forever. For Windows one used to have to rely on CgyWin before the virtualized WSL platform came to be.
Whilst MacOS has the somewhat opaque ~/Library for storing user settings and data, it pales into comparison to the massively Opaque Windows Registry.
I’ve had had very few issues fixing app install issues with my Mac - with Windows I’ve had more than one occasion where I’ve had to do a complete reinstall of the OS due to the Registry being totally hosed to the point I couldn’t reinstall apps again.
I think Windows is up there with the open source OSs (Linux, BSDs, etc) on regular PCs are at the same end of "run anything you want from wherever you want it", iOS devices are at the other extreme of "only run things approved by Apple", Android devices are pretty closer to iOS because they make you jump through hoops and potentially lose access to various functionalities to install certain things or gain root access. Modern macOS, as far as I understand, is somewhere in the middle: you have to jump through quite a few hoops to install certain kinds of software, and a few aren't permitted at all I think (unsigned kernel modules?).
You can run Windows almost on any hardware. So it is much more open in general.
You can equally run almost any imaginable software on both operating systems (if we ignore the performance), but you have extreme difficulties to run macOS on most hardware.
In terms of the machine Windows is way more open in that you can use what hardware you want. But yeah the software is closed source.
