OK. The Apple A9X processor in the iPad Pro is now 64-bit, with single core performance equal or better than that of the Intel processors in the MacBook Retina and mid-model MacBook Air. Has this changed the likelihood of a MacBook (e.g. with a keyboard, trackpad, and OS X) running an ARM processor (for the OS and apps) instead of an x86? How long might it take for Apple to introduce such a model? (And I assume that Apple wouldn't kill existing Mac models with Intel processors for those customers who need BootCamp or native performance VMs).
If Apple ports Xcode and Terminal to ARM (and a few other apps, such as Pixelmator got ported), I'd might get an ARM MacBook for my primary machine (as I don't run legacy apps daily). I assume (perhaps incorrectly) that an ARM (A10X?) MacBook would either be a bit lighter or provide slightly longer battery life, plus have higher performance graphics.