It is more like, yeah we blew it, but the cost of new tooling for injection molding an updated case would increase the cost of the (very low volume) device too much to reach a price point that would be accessible to as many hackers as possible. We'll add the port on newer revisions of the board, so you can either embed a card inside the device, or make/modify your own case.

Lots of hackers all around the world don't make anywhere near the incomes of e.g., SV developers. So, this is more, "Lets keep the price down to make the community as large and inclusive as we can." The projected price point of the e-reader is, unfortunately, already too high for many.