I think the home energy battery angle is interesting but as others have pointed out the commodity aspect and not being excited about it enough to prefer Apple to other more commodity based solutions is significant.
I think being able to combine AR with AI to control a multitude of smart products would allow Apple to leverage its strengths of providing people with a compelling experience that just works while allowing them to express themselves as individuals. This will require networking with other companies rather than a solution they can pull off on their own. It’s interesting to speculate on how Apple would be able to engage players like Google, Amazon, Facebook, and traditional manufacturing companies into participating with them while still being able to maintain their premium brand.
Perhaps Apple can acquire enough significant technologies that they can create life styles which are so attractive that other partners will want to participate rather than be left on the outside while Apple takes a cut when these partners join their AR/AI life style network.
Batteries would be just one component of a much larger and far reaching strategy of being able to monetize the seamless integration of the products we surround ourselves with. The vision is one of feeling more in control so we can express and see ourselves reflected in all aspects of our lives. This approach would address the alienation associated with an endless stream of technologies we don’t understand or trust which contribute to our fear and anxiety rather than relieve it.
Once we entered the industrial revolution, people have come to serve the machine much more often than the machine has served us. Integrated products which reverse this trend would fill this void and add value to our lives that current products can’t.