I don't think people are aware of ARM's histroy. The ARM processor was first created for the Acorn Archimedes in the late 80s, which was a personal computer way faster than the IBM clones of the day. The first mass production PC with a true RISC processor.
Even when that minority platform was on its last legs the StrongARM chip of the mid 90s again saw Acorn boast a machine faster than the Intel PCs of the day.
ARM chips are just plain better designs than Intel's hoary old system. But their extremely low power consumption made them perfect for the embedded space and that's where the company headed. They could have targeted the desktop space or the server space but with other chip dominant there what would have been the point? They had success in embedded markets so targeted that space and the rest is history.
With big players like Apple signed up to use desktop and server class ARM chips I have no doubt the company would out-innovate Intel for years. It's just better, slicker, cleverer tech.
I more than agree with your comment. On the mobile what is more important is battery life. What is CPU power worth if you could only last 2 hours? Decent processing power and longer battery life is what Apple is looking for.