The Underlying Theory of Project Management is Obsolete
I would want to point out some piece of tacit or unspoken truth –many people know it but very few actually behave accordingly– that most current project managers still believe in many rotted ideas from the past.
L. Koskela and G. Howell, (2002), "The Underlying Theory of Project Management is Obsolete" Proceedings of the PMI Research Conference, 2002, 293–302, available here
In brief, there is a theoretical foundation for project management as promoted in the PMBOK Guide by PMI and mostly applied in mainstream practice but this foundation is obsolete and has to be substituted by a wider and more powerful theoretical foundation.
Where have they been?
Making money? That is ok, as long as it is not the only thing they have done.
There are others managers, though, gaining kind of humbleness that enable them to learn and reflect on other ideas with associated very good results (sustainable results that include money and more).
See for example: