Windows could probably run on ARM tomorrow (or at least, in 6 months) if Microsoft really wanted it to. What it could probably not do is run-on-ARM with accept

Windows could probably run on ARM tomorrow (or at least, in 6 months) if Microsoft really wanted it to. What it could probably not do is run-on-ARM with acceptable performance for every legacy app. Windows' bread and butter has always been forever-compatibility (Win API language-of-the-year aside) for long lived business apps. Apple has never, and doesn't seem to want to, competed on that front.