The Quote from Publisher's Weekly is not, I think very sound. Lets look at it in detail:
Manuscript publishing and Gutenberg: Yeah it is true that Manuscripts did survive for a while. That however was more because the costs with setting up a print run were substantial and for many more specialized books, in an era when literacy rates were low, it was not profitable to print them. However, when was the last time you saw someone commission a new Manuscript? Outside of copies of the Torah anyway.
News papers did not kill printed books for the simple reason that news papers never targeted the same market.
Radio may not have been killed by Television, but it was radically altered. The radio of 1940 was filled with many dramatic and comedic presentations; by 1960, radio had been taken over mostly by music with many of the programs formerly on radio migrating to television.
Need I go on?
To put it in simple terms. Ebooks may not spell the end of print publishing, but they will dramatically reshape the print publishing landscape.