I expect they just buy the e-ink panel from someplace. Its cost will include any such fees. Small panels are expensive compared to alternatives, but not THAT expensive. Example: https://www.adafruit.com/product/4687
As with almost everything nowadays, it is about volume. If you're Apple and you're buying a million displays an order, then that's the tier 1 price which is where the price is dominated by the actual material costs and buyers are arguing about the cost of Indium or silicon that went into the package. At the complete other end is single unit distributors where the price represents the markup every other layer of distributor put in. The only time a single unit distributor is able to offer a good price is when some tier-1 buyer decided to dump an entire batch because it has some aberration that they can't tolerate but someone who's doing stuff by hand can.
