For the record, the "patents" think has no links to back it up either.
But to answer your question: E-ink screens are less than $100 (depending on the size), that's already pretty cheap. They're only expensive when compared to LCDs. LCDs are produced at a rate of billions per quarter*, with ~6 billion smartphone owners, and lots of them having multiple LCD devices e.g. laptop/desktop screen, work computer's screen, supermarket kiosk, tablet, smartwatch, car screen, etc.
In contrast, e-ink screens have basically three applications: e-readers, e-notes (which is basically just an e-reader with a stylus), and supermarket pricetags. E-readers/e-notes are a luxury item that you don't need if you already have a smartphone/iPad. There's just no economy of scale for e-ink; not compared to LCDs.
Because there's no economy scale or obvious new markets to expand into, there's not much budget for R&D, so the entire field moves slowly.
If e-ink was x100 cheaper, we could use it in x1000 more use-cases
Giant E-ink screens are expensive because they're made by fusing together 4 smaller e-ink screens (4 of 10.3" or 13.3" screens IIRC), but the process is expensively done by hand because there's simply not enough demand to warrant automating the process. There's just no money in giant 1Hz monitors.
For example? What untapped use cases would be if e-ink displays which can only show B/W images and refresh at 1HZ, unable to show full motion video, and suffer from terrible ghosting, would be cheaper?
I think you're deluding yourself here. Cheaper prices won't magically fix the major limitation of this technology that hinder its expansion outside of its existing niches: e-readers and price tags. All the other display markets have been conquered by LCD, MIP and OLED already because those technologies work better in those cases and e-ink works better where it already is.
I don't know if there is a big market for any of that stuff, but certainly there's not a lack of ideas. A lot of things that aren't worth it at the current price point become viable if the display weren't so expensive.
We'd all like many things, but that doesn't mean there's a mass market for them to warrant significant investments that would guarantee a decent profit for the investors.
It seems that you have a e-ink hammer so everything looks like a nail to you, but sometimes pen and paper or a plastic white-board and a felt pen are better and cheaper than a big e-ink display that needs to be recharged.
And E-ink smart watches have been made in the past but sold much more poorly than OLED one so manufacturers dropped in favor of OLED. MIP is a thing though in some Garmins.
The core problem hasn't changed, though: LCD covers more use-cases than e-ink does; it even has better battery life than e-ink in some scenarios! (E-ink screen refreshes take a lot of energy more energy than LCDs, although they only refresh once per interaction instead of 60 times a second)
E-ink sounds cool (and is cool), but it's not practical. It's the zeppelin of electronic displays.
Even niche early adopter users at current prices don’t love the tech