First, books are not all entirely sequential. One of the reasons I still buy paper books on IT is that I reckon I can often find what I want faster than by searching. Yesterday I wanted to remind myself how to iterate through a directory using Perl. I know the recipe is in "Perl Cookbook". I know that book is within arm's reach. I remember the chapter is about a quarter of the way through. Flick flick - bingo, all in about ten seconds. If I don't know the book well I look at the contents page, which is no slower than skimming links on a screen. Yes, I'm sure a computer is faster in theory, but that isn't my subjective experience, and I don't think that's because I'm incapable of using a computer. Grabbing a book and flicking to roughly the right place is actually not a bad random access heuristic.
Second, sequential is often good. It often *is* the pedagogy. When I first get a book (not a cookbook...) I often start on page one and read to the end, maybe skipping bits that really don't interest me. Yes, that takes longer if I'm looking for one specific answer. But, if the book is well-constructed, it often gives me a much better feel for the overall subject than I would get by looking at 200 modules, each of which is designed to stand on its own. And, in practice, I'd probably only read 20 of those 200 modules because there's no narrative to pull me onto the next module.
A great example of this for me is "Mastering Regular Expressions" by Friedl. You can google most of the answers to specific regex problems, and I did that a lot. Ploughing through hundreds of pages of dense and often obsessive text (breaking off from writing a chapter to get Richard Stallman to patch emacs regexes counts as obsessive, right?) meant that I finally understood how regexes work, what happens under the hood and why some apparently innocuous regexes never terminate.
Hypertext and modularity have their place. But I wouldn't dance on the grave of sequentially structured information just yet.