P!
As usual, blame the "computer engineers". As a sort of one of those, I could probably get most data from 49 systems in a few weeks, but I would have to leave out some. I could get a lot of useful functions done in a few months, but would take a lot longer if required to do stupid or pointless ones. The more staff I was given, the longer and more expensive it would be, particular if I had government reviewing and approving requirements. Given enough system engineers overdesigning and government stupidity I could easily see spending 1/2 billion.
The system was so expensive because of the several sets of accounting required and the built in future features to switch from dollars to vouchers and eventually to payment in toilet paper.
I’d bet dollar to donuts that the entire Project Management team did not consist of a single qualified eningeer, that each had such “credentials” as a Project Management Professional (PMP) 12 week-wonder certification combined with BA or business degrees, and that the entire project was in chaos from day one, that there was no adult supervision of the project and everyone was playing politics.