Originally Posted by Hellmark
General purpose devices always win out in the long run, because to the unwashed masses they're "good enough".
That's only true if they possess the same qualities, by and large, as the specialist devices. Calculators may be a bad example; if I need plotting, equation solving and the rest of the advanced stuff I use my computer, while for a simple addition my cell phone will do. The middle ground is really small here. Even so, dedicated devices exist, and cheaply at that.
Why should that be any different with ereaders? I can read epubs on my cell phone, if I must, but I don't enjoy it. Ereaders have superior displaying capabilities and battery life. General purpose devices will have to address these issues first.