Mobile Phones Hurt Manga?

Mark Frauenfelder's journal has him posting from Japan, where he is surprised at how things have changed on the subways and trains there since his last visit. When he was there fourteen years ago, everyone was reading manga while riding the trains, but now everyone has mobile phones that they use instead.

A part of what made manga so popular to the Japanese audience, was it was something easy to carry and read while you commuted to work. Now with other options available it is understandable for there to be some decline, but I doubt its as drastic as the Markpaints it.