> they seems to be hard to find as a full set at a decent price
All of Knuth's work on TAOCP since Volume 3 (basically everything that he's written for 4A and 4B, starting over a decade ago) is essentially available for free online, in the form of preliminary drafts that Knuth put up online. You can find them nicely collected here: http://www.cs.utsa.edu/~wagner/knuth/ Of course the pleasure of holding a beautiful hardcover book in your hand is missing, but all the content is mostly there.
To answer your earlier question, not many people have read all the books in their entirety, though there are a few. This is simply because the books go very deep on their topics, and most people would prefer to just dip in.
I read a few pages of one of the recent fascicles a while ago, doing all the exercises etc. It was a lot of fun, and also took about a month to read about a dozen pages. But the experience was rewarding (also got a check from Knuth!), and the writing in TAOCP was easier to understand than it would have been to read the original papers that he had digested. (Comment about this a few months ago: https://news.ycombinator.com/item?id=15035767)
All of Knuth's work on TAOCP since Volume 3 (basically everything that he's written for 4A and 4B, starting over a decade ago) is essentially available for free online, in the form of preliminary drafts that Knuth put up online. You can find them nicely collected here: http://www.cs.utsa.edu/~wagner/knuth/ Of course the pleasure of holding a beautiful hardcover book in your hand is missing, but all the content is mostly there.
To answer your earlier question, not many people have read all the books in their entirety, though there are a few. This is simply because the books go very deep on their topics, and most people would prefer to just dip in.
I read a few pages of one of the recent fascicles a while ago, doing all the exercises etc. It was a lot of fun, and also took about a month to read about a dozen pages. But the experience was rewarding (also got a check from Knuth!), and the writing in TAOCP was easier to understand than it would have been to read the original papers that he had digested. (Comment about this a few months ago: https://news.ycombinator.com/item?id=15035767)