If you have an iPad and you leave your house in the morning, you can be gone all day, use the thing for 10 hours, and come back home never carrying anything other than that thin device. Laptops aren't quite there, but close. If I leave my house in the morning with my Macbook Air fully charged, I can get about 7 hours out of it. Provided I eat lunch and am not in front of it for the full seven hours, it lasts a workday, and I don't need to carry a charger. But that is not enough. I want to be able to perform processor intensive activity all day like watching video, and then take it with me to a coffee shop or wherever after work before I go home and still not have to plug in. Currently, the great battery life of a tablet comes from the utilization of the power-sipping ARM chip. ARM architecture powers mobile, but not laptops. Intel is working on low power solutions for laptops, and there is talk of Apple moving the ARM architecture into their Macbook Air line (though this is still speculation at this point). Either way, the trend is clear, and we're going to get improved battery life on all of our mobile tech through a combination of processor architecture and battery improvements. I already have a hard and fast rule about buying my next laptop. I will not ever purchase another one until the laptop sports a full Retina quality display, and battery life over 10 hours. If it doesn't, there's just no use-case incentive for me to get another. I don't believe I will have to wait too long. Maybe a year, -two max.
Also, I don't know much about software engineering, but don't new processor architectures require new programs designed especially for them? I'm reminded of Apple's change from PowerPC to Intel and all of the backwards/forwards compatibility headaches that that caused. Now Microsoft is saying that Windows 8 ARM devices won't run x86 apps.
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.
In any case, I'll be rooting for more efficient Intel chips.