Earlier quoted context omitted.
Looking up their patents ( https://patents.justia.com/assignee/e-ink-corporation?page=3... ), looks like their earliest patents are from 1998, so those should be expired already. That said, there's 36 pages of patents that seem related, so I'm sure that newly made e-ink technology will be covered by the newer patents.
It also takes time for manufacturers to design and produce. Even if someone had rushed out of the gate in 2018, they would probably not have ad products ready for a couple of years (and last year there was covid too) - and this with the most basic tech, which we know actually took significant time to be refined. I think a more realistic timeframe for usable eInk patents is 20 years from the first Kindle release, so 2…
Ignorant question: are you not allowed to start developing a product, or "planning" to develop a product, before a patent it infringes on expires? I see from glancing at Wikipedia that with a US patent, "making" the item is infringement, but where is the line on that? Is it that you literally can't fully make the thing, i.e. only get 99% of the way there and you're fine? Or is it infringement to have an on-the-record chat with a buddy that you're thinking of working on X when the patent for X expires? (Responses in the form of LMGTFY are welcome, I couldn't quickly figure out how to search for this.)