What would I do with a A-series macbook? Run Microsoft Office... no... wait... That's built for x86. Okay, run ____. Nope, also built for x86. Run Windows under bootcamp or virtualization? Nope.
Well, I suppose you could browse the web, but then it's little more than a chromebook - and a freaking expensive one at that... at least until others work through the platform transition and make fat binaries like its 2006 all over again.
Well, I suppose Apple could make a iCloud service to host your x86 apps in the cloud and deliver them to
MS already ported office to iOS and is available in the app store. I downloaded it and have it on my ipad - but I still use iworks. There are some unique software and high graphics games that are not available in iOS, but generally what longfest pointed to (the 80%) is already covered in iOS. Apple does not do serious gaming because they don't do serious GPU processors. As that is true, the minority of gamers will stick to x86 machines where they can customize the hardware to fit their needs. For Apple to play in that area, is years away. For just about everything else you dont need MS.