As I read this thread, I can't help but think back to the days when dedicated mp3 players were first coming online. The huge music lover I am, I was definitely an early adopter of mp3 gear back in the day. And lemme tell ya - there weren't a whole lot of us back then sporting on the go digital tunage.
Same thing with dedicated ereaders IMO, though admittedly, the scenario now is complicated by the relatively new existence of do-it-all smartphones and such.
I do totally agree with the person who wanted to quantify the term "popular". There's a whole lotta people in this world. P books have been around for millenia, ereaders and digital books for a fraction of that time. But every day that passes, more and more people are aware of the "digital" option. Will it change the traditional p-book paradigm overnight. No.
But eventually? Maybe
However...given the current mass hysteria re: Apple products, and their brilliance at creating a sense of nearly irrational lust by consumers for their stuff, I would guess that if Apple ever decided to market a "pure" ereader [that was even remotely reasonable in price], this might push more people into wanting such a thing. The exact same thing happened with mp3 players when they stormed into the field.
my 2cents FWIW