How so? I am sure that there might be some who would prefer to read a work as difficult (and intricately typeset) as TAOCP on a screen instead of paper, but I imagine they'd be a minority.
Despite what some may say TAOCP is a very readable series of books. But they do require being read in hardcopy, at a table, with a pen(cil) and notepad.
This isn't something you read on your Kindle while taking the Subway uptown.
No offense again, but all of the replies to my comment are equally ludicrous. If it were digitally available, you could search and index it, text mine it, distribute it to people in poorer countries, carry it with you when you move a lot. These are all the obvious advantages of ebooks, and nothing about TAOCP makes it especially necessary for a digital version. To make an educated guess, the problem must be some part of Knuth's attitude to life - he spent a major chunk of his life designing a system to make things you type in from a computer look good on paper.
Edit: to clarify, I'm not saying it shouldn't be on paper - freedom of choice! - I'm saying it should also be available digitally. And to the person who said that TAOCP is only a collector's item, you're completely ludicrous.
