That's a good point. I should have said that I think the author missed the implications of increased Prime subscriptions.
The fact that other people made comments similar to mine tells me that the author's post read as though he hadn't thought through the long run advantages to having prime members, and how average people (and not just the author) are likely to behave once they realize they can get almost anything shipped to their door.
However, you're correct that he did show awareness that this might be amazon's strategy. If he wrote more on this specific point, he might actually agree with everything said here, but have some other doubts we haven't addressed. Who knows.