Why has The Mythical Man-Month persisted? Why is it still seen to be relevant to Software practice today? Why does it have a readership outside the software engineering community, generating reviews, citations, and correspondence from lawyers, doctors, psychologists, sociologists, as well as from software people? How can a book written 20 years ago about software building experience 30 years ago still be relevant, much less useful?
One explanation sometimes heard is that the software development discipline has not advanced normally or properly. This view is often supported by contrasting computer software development productivity with computer hardware manufacturing productivity, which has multiplied at least thousand fold over the two decades. As Chapter 16 explains, the anomaly is not that software has been so slow in its progress but rather that computer technology has exploded in a fashion unmatched in human history. By and large this comes from the gradual transition of computer manufacturing from an assembly industry to a process industry, from labour-intensive to capital-intensive manufacturing. Hardware and software develoment, in contrast to manufacturing, remain inherently labor-intensive.
A second explanation often advanced is that The Mythical Man-Month is only incidentally about software but primarily about how people in teams make things. There is surely some truth in this; the preface of 1975 edition says that manging a software project is more like other management than most programmers initially believe. I still believe that to be true. Human history is a drama in which the stories stay the same, the scripts of those stories change slowly with evolving cultures, and the stage settings change all the time. So it is that we see our twentieth-century selves mirrored in Shakespere, Homer, and the Bible. So to the extent The MM-M is about people and teams, obsolesence should be slow.