Eink displays only use however much the battery inherently loses when not changing pages. If you only read 500 screen of text that month then it only consumed a trickle of battery x 500. Your screen itself consumes power every second its on and you also ask much more than rendering text.

What you propose is interesting though none the less. What is the most battery life that can reasonably be packed into a device that is modest but still useful.

Sure, but that won't come from people programming differently. The laptop backlight alone is a few watts. If your battery is 40 watt-hours, you're not going to get to 2 weeks of usage no matter how little the CPU gets used.