Hardware

Users don't care about the processor architecture but they definitely care about battery life and the word is getting around. I work in a mostly platform agnostic environment where the worker can choose whatever they want and the Macbook uptake has been enormous over the last few years, so much so they are planning on phasing Windows out entirely in favor of Chromebooks and Macbooks (both backed by Citrix virtual apps for legacy applications).

If Microsoft ignores this inevitable evolution away from x86 twenty years from now it will comparable to when Ballmer laughed at the iPhone.