[fjtorres]

His arguments aren't bad and pretty much in line with Bill Gates' old observation that "people tend to over-estimate the impact of new technologies on the short-term and underestimate their impact in the long-term".
The thing is, the example he uses, the digital music business is *not* a perfect model for the book industry. Digital music downloads are not by nature a substitute for CDs but rather a supplement; they arose because the music studios did not provide a replacement for the old 45rpm singles and there was a market among followers of Top-40 music for an inexpensive format that didn't require the purchase of a full CD. In addition, for people who *do* like to buy a full CD of music, the CD is *still* more economical and flexible to buy and easily transcoded, aka, "ripped" into DRM-free tracks.
Thus, I would posit that digital singles may have actually peaked in popularity and that CDs will likely endure indefinitely (or until the studios wise up and introduce a new, more compact physical media product to replace it. But since the same studios are now 15 years+ late in introducing the CD replacement...).

Books, of course, are not as easily converted into ebooks.
And ebooks are in fact a full replacement for print books; unlike compressed music downloads that offer slightly lower quality that their CD incarnations, ebooks are lossless conversions of the original material.
Also, while a significant portion of book buyers do like to collect and retain their purchases, there is also a significant (probably larger) portion that considers books as disposable entertainment. Unlike music with has extensive replay value, books are often once-through purchases, which adds value to the mass-less quality of the ebooks.
Finally, unlike music, which even in digital form is still relatively bandwith-intensive, ebooks lend themselves to near-instant gratification over existing wireless networks, thus providing added value in accessibility. (The calling card of the Kindle and Nook platforms.)

To me, all this suggests to me that ebooks offer adopters more value compared to print book buyers than commercial music downloads do compared to CD buyers. Indeed, the case can be made that for *album* music buyers, CDs are a superior delivery mechanism and often cheaper. While the BPHs are trying to price ebooks high enough to protect their investment in print books most other publishers are more than happy to ride the ebook superior value proposition to a larger market share.

So, I would respectfully suggest that, while the pundits and analysts are very likely miscalculating the speed of ebook adoption, they are just as likely to be underestimating it as overestimating it and that unit sales parity is going to come to ebooks faster than to music downloads. (Where it may never actually arrive without a further disruption and newer business models.)