I would say it's a huge price for something able only to display PDF files.
I understand this is a premium product, linked to a designer object, but this is probably not enough to become a mass product. I am not sure that Sony wants this either
aggressively promoting a product as an elitist totem keeps the price (and revenues) high - unless this concept would be copied by the archenemies.
In my opinion, this would be another item in the Sony's Museum of Unfortunate Inventions (along with MicroMV, MS, Digital8 and the like).