I am also not a software engineer, and can't speak to the architecture and how it would have to integrate with the applications, including the OS. But I think I can speculate that any prototyping and movement that say, Apple, is making towards shifting their laptops to ARM will do so in a way as to not break the production environment for developers.

But it might not even be ARM on OSX. Intel is running on all cylinders playing catch-up to ARM with a low power chip, so when they bring that to market, Apple and Windows based manufacturers might just be using that.

I was thinking the other day about how Apple is rumored to be slimming down their MacBook Pro line, -maybe even dropping the optical drive. I was wondering how they would then differentiate between the Pro and the Air line, especially if they look very much the same. It's possible that chip architecture could be one of the main factors, having an ARM based, low powered and efficient MBA next to a comparatively high powered (processor-wise) MBP running on Intel.

Any way you slice it, they're working on liberating us from our charger bricks on our mobile devices. Such a huge selling point.