In his subsequent books, especially those on Microsoft and Netscape, Cusumano slowly discovers that the traditional software development process, requirements/specifications/code, etc., e.g. the waterfall model, is *NOT* the model adopted by successful software companies (and, indeed, not the model adopted by many hardware companies). He learns that designs are not something to be churned out by a factory - indeed, if they can be churned out, then they should be reusing exactly the same software.
In some ways the packaged software industry, e.g. Microsoft, supplanted the custom software industry in this timeframe, the time of the PC; Microsoft's process, which Cusumano calls "synchronize and stabilize", may be considered to be JIT (Just In Time) software specification and development. Or, if not Just In Time, As Soon As Possible and No Earlier than Necessary.
While I cannot agree with the conclusions of this book, it is interesting to have on one's bookshelf, to see the evolution of the author's thought over time.