Quite frankly there are also a lot more boring answers as well, like they need email, they need a cloud office suite, they need servers to run their interanets, more than half a dozen stupid servers and applications that don't quite work right but have to be kept around because it is someone's pet project or X dollars was blown on it, etc. Think of the biggest organization you've worked in think of all the bureaucracy involved and all the stupid decisions and politics and now multiply that by having the CEO change every 4-8 years, people in the millions and just to make things even more fun the executives that make all the decisions are congress.

If anything I don't know if $10 billion is going to be enough for the level of crazy that can go on in the government.