Why Windows must die. For the third time: "Win32 still is the predominant legacy programming API. More apps out in the wild use it than anything else. And that subsystem remains the most significant vector for malware and security threats."
http://www.zdnet.com/article/why-windows-must-die-for-the-third-time/
If you've never converted something to use .Net, please be grateful.
People only use the Win32 APIs still because .Net blows for anything short of developing a brand new application from scratch with a fresh workforce expecting to never write for anything other than Windows ever.
If you want something in any way cross platform, to reuse any old code, or keep your existing developers it's a non starter. And always has been.
This can be sumarised very easily:
As it saysbin the article - it took Microsoft 16 years to convince themselves to move their own flagship applications away from the Win32 API.
Windows created the .Net framework bizarrely to userp Java and in a cynical effort to stovepipe developers in to only being able to write for Windows.
They talk of standards... but they're Microsoft standards available only on Microsoft systems.
The plan backfired due it being ridiculous to expect developers to go out of their way to make themselves unemployable outside of Windows, and their products unsellable outside of Windows.