"If we worked hard to keep OS requirements to a minimum- could we be looking at unimaginably improved battery life? Hyper reliable technology that lasts many years? Significantly more affordable hardware?"
Volunteer-supported UNIX-like OS, e.g., NetBSD, represents the closest to this ideal for me
I am able to use an "old" operating system with new hardware. No forced "upgrades" or remotely-installed "updates". I decide when I want to upgrade software. No new software is pre-installed
This allows me to observe and enjoy the speed gains from upgrading hardware in a way I cannot with a corporate operating system. The later will usurp new hardware resources in large part for its own commercial purposes. It has business goals that may conflict with the non-commercial interests of the computer owner
It would be nice if software did not always grow in size. It happens to even the simplest of programs. Look at the growth of NetBSD's init over time for example
Why not shrink programs instead of growing them
Programmers who remove code may be the "heros", as McIlroy once suggested ("The hero is the negative coder")