Okay, so referring back to the "ebook bubble" article, I think the question at issue is really "What is a bubble?" Saying that there is a bubble of anything really implies that something out-of-control will catastrophically burst, never again to recover.
People freaked out during the dotcom "bubble" and thought temporarily that everyone was foolish to believe people could make money on the Internet. Now look what's happened. Amazon is giving Walmart a run for it's money. Surely there will be crests and troughs in the ebook market but it seems like wishful thinking to think that the overall trend will be anything but upwards.
Mr. Konrath's take on the article:
http://jakonrath.blogspot.com/2012/0...ok-bubble.html