The customer already threatenes with penalties or even with compensation claims which can go into millions on large projects.
The best staff has been placed in the project. Everyone has delivered a very good job in recent times, people have worked to exhaustion. No serious failiures could be identified.
However, if the course of the project gets analyzed, then you will always find the same cause. I myself saw it often when I was called for "troubleshooting" into a formerly mismanaged project.
Usually a professional in the project management is missed, not available. The project management is often serviced by one of the staff-engineers "on the side".
Besides, everybody knows that a football team, even if it has the best football players, would not bring any good results without a professional trainer.
Nobody can imagine an orchestra without a conductor. Even if the best musicians play without a conductor, would not come out with a good piece of music.
In project work, it is the same. Only a good "conductor", in a larger project, can bind the synergies of the staff and optimize it towards a good success.