You seem to have missed out on the fact that the author has actually originally written a book that satisfies his criteria. The problem isn't fixed merely by a

You seem to have missed out on the fact that the author has actually originally written a book that satisfies his criteria. The problem isn't fixed merely by adding more content. The point is that there is value in a certain style of book that integrates an introduction to a technical topic, a concise description of the algorithms and data structures involved, and then a real-world application of the technique to an actual problem. The author's book, Programming Collective Intelligence, is only ~350 pages: the problem isn't a lack of space, the question is how book authors ought to use space that they have available. Whether books should be 1000 pages or 2500 pages is beside the point.