Technology disruptions are tricky things. We usually don't see breakthroughs coming, and we certainly don't realize their societal and business implications and impact until they are already well underway. (Check out The Innovator's Dilemma, by Clayton M. Christensen, to get some perspective.) Think about the jet engine, the Internet, and the ball-point pen, as examples. Even our industry, which boasts of its reliance on innovation, is not immune: none of the market leaders in vacuum tubes succeeded in the transistor and IC market; and only a few of the transistor leads remained as major players when ICs took over.
But even though we can't foresee disruptive technology events, it's still interesting to speculate. Recently, when I was looking at another ultra-low-power IC, and I had just finished reading a story about low-power design strategies, I started to daydream and pondered, “what if someone came up with a battery that had 10 or even 100 times the energy density and power capacity of today's best?”
Lots would change, and some things would not. For applications which are primarily constrained by their ability to dissipate heat, things might stay pretty much the same. However, for applications where run-time is the key factor, many underlying design premises would change. Circuit designers would be able to choose among many more available components, some of which have superior specifications compared to their lower-power siblings. Complex, software-driven algorithms to implement selective, smart shutdown of portions of the circuitry or IC could be abandoned. The teams of skilled IC designers who conceive and implement clever silicon topologies to minimize power dissipation could instead work on other performance attributes.
It wouldn't be only the application-focused ICs and their circuitry that would be affected. Complex battery measurement and management might not be needed in many products. Charging circuitry and ac-line adapters might have to change dramatically, as well. The form-factor of the end product could have new flexibility, since a denser power source means a physically smaller battery would be sufficient for applications where longer run time is not a primary requirement.
I realize that a battery order-of-magnitude breakthrough is not likely in the immediate future (of course, you never know for sure). But even if it is not, it's useful to think through the “what if?” aspects, since this forces you to articulate the underlying assumptions of a design. These assumptions are so fundamental to the design thinking that they are often not even formally stated. By going through the what-if process, you expose them and review if any of them have changed and if so, by how much. That's a good thing to do periodically, even in the absence of an actual breakthrough.