It is also in part a factor of the way procurement works, many beancounters still can't grasp that needs vary and problems happen, so you get a budget, if you come up below budget you lose the extra and may get your next budget lowered to match, and getting more budget is a hard fight.

As a result, departments want to have a budget as close as possible to a worst-case scenario, spend the entire year thrifting in case something major occurs and then have to blow it all up right before EOY.