>And then the e paper panel costs a bunch so what would be a $1000 laptop becomes $4000 and is strictly worse for the vast majority of users.
IMO, this is fundamentally a niche object. But that nicheness means that if it did exist, it would have several options without worrying about pissing off the mainstream.
#1 on that list is that you don't need to seamlessly emulate an LCD screen with an e-ink screen - instead of having a single multiplexed screen, have 2-3 80-char-wide separate e-ink screens and have text on each of them.
This has two advantages: one, it's cheaper because e-ink screen costs scale geometrically with size, not linearly. And two, AIUI partial-refresh doesn't work well when you're literally refreshing a third or half of your screen, but two completely independent screens can obviously refresh independently of each other. I'm assuming partial refreshes are faster due to taking a smaller absolute number of pixels, and not due to being a smaller proportion of the screen, so e.g. a quarter of a 4" screen will refresh the same speed as a full 2" screen refresh but faster than a full 4" screen refresh.
Ideally, you'd want to split the e-ink screen into as many smaller screens as possible anywhere it makes sense (and design the UI in hardware), simply to reduce costs.
Sadly, large cheap single screens have made the concept of software controlled UIs so obvious that people don't even consider the alternative.
IMO, this is fundamentally a niche object. But that nicheness means that if it did exist, it would have several options without worrying about pissing off the mainstream.
#1 on that list is that you don't need to seamlessly emulate an LCD screen with an e-ink screen - instead of having a single multiplexed screen, have 2-3 80-char-wide separate e-ink screens and have text on each of them.
This has two advantages: one, it's cheaper because e-ink screen costs scale geometrically with size, not linearly. And two, AIUI partial-refresh doesn't work well when you're literally refreshing a third or half of your screen, but two completely independent screens can obviously refresh independently of each other. I'm assuming partial refreshes are faster due to taking a smaller absolute number of pixels, and not due to being a smaller proportion of the screen, so e.g. a quarter of a 4" screen will refresh the same speed as a full 2" screen refresh but faster than a full 4" screen refresh.
Ideally, you'd want to split the e-ink screen into as many smaller screens as possible anywhere it makes sense (and design the UI in hardware), simply to reduce costs.
Sadly, large cheap single screens have made the concept of software controlled UIs so obvious that people don't even consider the alternative.