Re: 2,400+
Not quite sure if business people will be crying out for these but the foldable form factor does have a lot to recommend it. And lots of teething problems to overcome as well, no doubt. But I can easily imagine foldables becoming the norm in a couple of years.
No doubt the screen is very expensive, which is also why a decent eink ereader is up to x4 price of a more complex smartphone.
Here the screen and hinge is no doubt expensive because complex. E-ink screens aren't complex but they're produced in much lower volumes which means a higher marginal cost so you can't really use them for a comparison.