Always on is pure marketing with very little substance. To tether my laptop to my phone takes about 2 seconds - unlock the phone, swipe down, click the button to turn on wifi tethering. Done, and I don't have to pay for a second cell line. That said, ARM has two big problems to overcome to compete with Intel in the laptop or desktop environment, software and price.
Even if their chips are more modern and more efficient, if they attempt to compete with a u series i5 on Windows, they're going to have to use 10 to 15W ARM parts to compete with 15W Intel chips to overcome the x86 emulation, so they really need Microsoft to do a much better job supporting apps designed and optimized for x86 on ARM platforms. But really I think that means they need all app developers to release builds for Windows on ARM and I don't see that happening until there is a huge demand for it.
Now assuming they do get that support, there is the pricing issue. The high performance ARM platforms released and announced so far that can run Windows 10 are flagship SOCs with flagship pricing. But they have to compete with Intel's main stream mid range chips that cost half what these flagship ARM SOCs cost. Actually, right now Snapdragon 835 is almost competitive with quad core Braswell (right up until x86 emulation comes into play), but a Braswell SOC costs a third what a Snapdragon 835 costs.
I think the only way they can penetrate the Windows laptop market is if they can both improve performance enough to be competitive (which right now they are no where close to) and cut the cost substantially to give people some incentive to be an early adopter and try out an ARM laptop even though the ecosystem of ARM optimized applications doesn't exist yet. They have to do both because no one wants a slow, crappy laptop at any price, and most people won't pay a premium for an acceptably quick laptop that can't run the software they need.
Now if they could just get away from Windows and take the x86 emulation out of the picture, they'd have a pretty good product. These would probably make great Chromebooks or Linux laptops. But again, pricing would be critical.