The basic storyline here won't surprise anyone who keeps up on such things: Ebooks aren't going to put print books out of print anytime soon.
This is the latest iteration on mainstream media's fascination with ebooks.
Back in 2000, ebooks were huge. Then everyone discovered that it wasn't much fun to read a 400-page novel on a desktop computer screen. The real takeoff for ebooks would have to wait for the introduction of a cheap, portable reading device.
Then Amazon came out with the Kindle in late 2007. Suddenly ebooks were huge again. Printers would be going out of business any day!
Now the media is cautiously pessimistic on ebooks again, because their market performance hasn't lived up to the original hype.
As organized and visual as the Forbes information is, it doesn't give the more important explanation: Some books (those with lots of graphics, maps, and tables) were never well suited for the ebook format. Nor are doorstop-sized nonfiction titles.
Ebooks are best for fiction, and concise nonfiction works that don't rely much on visuals.
That doesn't mean that ebooks are "failing" or even "fizzling". It simply means that ebooks, like print books, have their ideal range of application. And that range doesn't include every book-related need.