One of the biggest challenges is that we're at war all the time, so shit moves around constantly and things get broken and lost and there isn't time to figure everything out. But the way accounting works for the DoD is that it's all cobbled together from old specialized systems to meet local requirements, and the systems do not interface particularly well. Records retention is not done as well as it should be, but more important than that, there's no fucking way that everybody is spend their whole day calling around to get people to pull records from filing cabinets, or to look them up. They have real work to do.
It needs to be re-tooled from scratch, the whole thing. But there will STILL be massive problems with accountability. It would be, by far- really really far- the largest and most technical and difficult accounting system ever designed. It's the accounting equivalent of landing on Mars. It can be done, but Christ. I can't properly explain just how fucking difficult it is to do that. Maybe somebody like
@PolishHeadlock who has big corporate accounting experience can chime in on that. I'm out of my element on this.