That you have to thank the traditional WinDev vs DevDiv political wars.

As usual the .NET product (XNA), got replaced by a C++ one (DirectXTK).

https://walbourn.github.io/welcome/

They acknowledged they should have behaved better, years later with the new management adding support for MonoGame on the XBox,

https://news.xbox.com/en-us/2016/03/14/letter-chris-charla-i...