How do you reconcile those being "musts" with the wild success of products that don't have them? Not even paper satisfies all of those supposed necessities.
Point taken. I would say that satisfying point 3 relieves the need to satisfy point 2 (if I can replace it for less than $50 then I can handle the possibility of coffee getting poured on it). So paper works.
Well, it's not trying to be a "tablet", so it's not lying around the living room. 95% of the time it's sitting in your pocket when not in use, very safe and comfortable.