A Single Hair at the End of a Very Long Tail

Interesting numbers from Chris Anderson's book The Long Tail (Hyperion, 2006):

In 2004, 950,000 books out of the 1.2 million tracked by Nielsen BookScan sold fewer than 99 copies. Another 200,ooo sold fewer than 1,000 copies. Only 25,000 sold more than 5,000 copies. The average book in America sells about 500 copies. In other words, about 98% of books are noncommercial, whether they were intended that way or not.

 I know I am not retiring on the royalties from my books any time soon.

What is the incentive to publish in print rather than on the web if there is no commercial advantage anyway?