Adam, Please! Access is not outdated. It is mature.
But the government uses outdated software sometimes because of the regulations regarding development of more modern software. If there is no package that does what they required (and in this case, required by act of Congress - literally), then they must "roll their own." Using leading bleeding edge modern software is considered high-risk. Using software with a proven track record of ability and compliance to regulations is low risk. We've had that discussion in another thread. It applies here.
You know that old phrase, "Sometimes it takes an act of Congress to get something done around here" ??? For the federal government, that is an exact description of the start of the project initiation process. Seriously.