If there's enough demand, they'll fix this. Especially after the patents run out.
It's almost never about whether a company can do something, but about whether they leave money on the table by not doing something else.
I see this mistaken assumption repeated everywhere by people unfamiliar with the display technology industry. You can attend display conferences and see lots of startups trying to make stable displays. The limitation is not patents. You can ask a simple question to prove this to yourself. Which E Ink patent is blocking progress and will suddenly cause the industry to become amazing after the patent runs out? At best, you'll get lazy answers like ALL of E Ink's patents.
And you can look up e-ink's dozen or so patents that still have about half of their lifetime left. They're pretty fundamental to the technology. I personally try not to patent bomb here on HN so I don't push someone into willful infringement.