Matrix resource management is the main project structure in most large companies. With it comes a disconnect between project and business goals on one hand, and departmental priorities on the other. Matrix managers are more concerned with handling their budgets and keeping their bosses placated than they are with business and project goals. Now they will strenuously deny this, but, as always, their actions never lie.
In the matrix world reality cannot be allowed to intrude until all the possible alternatives, no matter how implausible, have been endless considered. Consuming time that puts even the reality based alternative in jeopardy. But the illusions of their superiors cannot be disturbed until it is politic to do so. During the Second World War when the allies surged ashore in Normandy the German reaction was hamstrung because vital reserves could not be moved with Hitler's express command, and he was asleep and no one dared to wake him! Times may have changed but human nature hasn't.
Now matrix world projects are always on schedule until it is politic to tell the truth - by which time it is too late to make any attempt to fix the problem. So when a PM creates a reality based project schedule that accounts for all resource constraints, queuing time in the system, and other obstacles that compose the “friction of life”, matrix managers are aghast. They don't want to change delivery dates from the previously published values, no matter how compelling the evidence is. They are the epitome of the "Bad news bears", you can tell them anything but the inconvenient truth!
I was laying out a project schedule and putting in a modest amount of queue time before development and QA. It was modest and nowhere near the real values, but since the management refused to admit there was queue time, never mind publish the values, it was the best one could hope for. Needless to say the owner of the project tried to push back on the delivery date and it took all my powers of persuasion to prevent it. In this case reality based scheduling prevailed, but in most cases it doesn't.
One thing must be understood, reality always comes through and when it does it usually bites, and bites hard.