His original article really failed to make the case against e-books, deliverying bold statements without proper supportive material. Now his subsequent article is just as weak, giving more bold statements without support. Someone should explain to him that when you put forth a hypothesis, you are supposed to offer a proper proof to support it, not throw out secondary information that doesn't make your case (but I guess makes you sound smart).
eBooks have the potential to replace all books when they reach a threshold that meets all the consumer's core expecations of a book and gives the core improvements are expected from a book's replacement.
When/how that threshold is met (if ever) is is the true question. For some it has already been met. For others, they have some additional requirements that have not been met yet (price, interface, ease of use, content, display, etc.). Manufacturer's will continue to progress towards those requirements as their market share increases.
We tend to call gadgets revolutionary (like the iPod) when they are able to meet enough new requirements that they get a disproportionate increase in market acceptance. But there are still many people listening to CDs (even LPs), so obviously even the iPod did not completely replace previous players.
The Kindle is a step forward that pushes us closer to that ideal, how close only sales will tell. But for some, like myself, it has finally met my core requirements to move me forward enough to replace most physical books and newspapers (though not all yet).
Is one better than another? That all depends on your personal requirements.