But, a good part of the point of .Net was that the managed code was in MSIL and being compiled to X86 down the line rather than by the developer, so the argument that ARM support requires a move from .Net really doesn't hold water.

I'm hoping there's more to this than meets the eye, but... Here's a test case for you. VB6 apps are supposed to be going out of support relatively soon, but there's a lot of them still out in the wild. The understanding had been to redevelop them in .Net, but based on this exactly what should the authors commit their investment to? Frankly if this doesn't get cleared up soon, for me the answer would be 'anything but Microsoft's stack' - it's just too unpredictable.