Re: Not too worried here.
Good ideas, and I'll clarify what I'd like. You can currently power the Pi from a battery, but its power consumption is much higher in all possible states than anything of the same capacity for computation. A phone tends to have a much faster processor, on which it runs a lot more software, and connected to more active peripherals and also runs on less current. That's partially due to optimization in software, partially the use of chips intended for mobile devices rather than chips for mains-powered boxes, and a few smaller factors. That makes sense for SBCs where they intended them to be used as desktops or servers, so a cheap chip from a TV box would do that fine.
I would try to just run the software on a phone except the software limitations make it harder to do many things with one; even a rooted Android device takes a lot of hacking to get anywhere close to the openness or configurability of an SBC. I already know that a device I can program with similar power to a Pi which can fit, battery and all, in my pocket is possible, and I can envision plenty of ways to use that power and portability. Now I'd like to buy that, but am only offered subsets of that in the hardware people sell. Since I couldn't buy it, I tried to build it, but all the SBCs around which I could try were Pi-like in power consumption. That meant either a much larger battery or much more frequent runs to recharge it.
This is possibly a somewhat minority interest. I've seen a few attempts and tried a couple myself, almost all built around the Pi itself or the compute modules, and all of them alluring but nonetheless limited by the same lack of power management. You can obtain something with long battery life if it uses a microcontroller, but of course that comes with limitations on what can run in that lower level of resources. I'm sure others have different revolutionary concepts, some of which would open other opportunities if they could be achieved. It strikes me that there was almost no revolution in the hardware of a Raspberry Pi SBC - the chips were common and used all over the place and the software wasn't new - except that they actually made, sold, and supported it to great effect when others didn't bother. That's kind of what I want here in a slightly different area.