I did not mean this as a criticism of the author. I understand it reads that way, and apologize. It is an attempt to question the base assumptions inherent in the analysis. As I put in another comment, and as someone else stated, the job of a manager is:

* ensure members of the group know what each other are doing. * ensure members of the team know where the team is going * act as direct report in another team that has another manager that does the same.

Any non-trivial software project will require parallel development. The biggest risk to any non-trivial software project is that when the pieces from parallel development are put together, they will not fit or inter-operate. In my experience.