People like to manufacture their own MI because it gives them a first look at the figures before everyone else. So if you're in the sales department and you manufacture the sales figures, you see them first. You can start thinking up excuses as to why you haven't hit your targets way before anyone else knows about the results.
2. The illusion of control
I'm not sure why this happens, but departments like to control their MI, because somewhere in their heads, it implies that they can control the business itself. Manufacturing your own MI only brings benefits if you do not have a data quality department.
3. Analysts have become too powerful
Very often the MI analysts know more, and make more business decisions than the managers. If their analysts were sucked into a centralised department, or made redundant, the manager would lose his/her competitive advantage.
4. You can bury bad news
Once you control your MI, there is a great temptation to only publish the data that supports the story that you want to tell. If any of your data contradicts the narrative, then it's just not important and often left out. Part of the climate sceptics arguments is that climate scientists are accused of omitting the results that do not fit with their hypotheses.
Centralising all management information functions brings a lot of important synergies to medium and large companies. But more importantly from a governance perspective, it takes the figures out of the control of the departments who have a vested interest in their results. Conflicts of interest occur less, and the data is queried and presented fairly.
To ensure this happens, it is vital that a Business Intelligence Competency Centre should almost be running as a separate entity from the rest of the organisation, and therefore free of the political control of vested interests from other parts of the organisation. As governance officers, I believe it is vital to promote a model such as this one.