Isn't the whole point of Windows that you can run your old shit on it?
I think the point of Windows is to run binaries I can obtain to get stuff done.
The Surface RT and Surface 2 weren't widely accepted because Microsoft made "Desktop" apps fail to execute unless they were digitally signed by Microsoft.
You could jailbreak around this in Windows 8, but not 8.1. Not yet, at least.
My RT ran lots of stuff I compiled for ARM just fine and dandy. Microsoft claim the digital signature restriction was put in place to prevent performance issues, but I think there is a lot more to it than that. People are used to dealing with performance issues on their computers, I don't see what an ARM CPU has to do with it.
So, when I say that "the point of Windows is to run binaries I can obtain to get stuff done" and when Microsoft prohibits people from distributing binaries meant to run on non-x86 processors, Microsoft seals the fate of non-x86 Windows platforms before it even releases them.