If I recall correctly e-ink took almost a decade to work out the very complicated processing required to produce displays with good enough quality control. It

If I recall correctly e-ink took almost a decade to work out the very complicated processing required to produce displays with good enough quality control. It was a really hard problem that required totally different tooling from a normal display manufacturer so I'd absolutely expect that to be a huge source of delays in getting set up. You can't just convert an existing display factory to make e-ink displays, so the startup costs are huge and the odds are good that you'll take at least a few years to work out the quirks. Probably more like 4-6... if you get lucky and can figure out what tools to use quickly.