alea, I think I've been stuck in some paradigm mud on this point at times ... counting DoD people is barely valuable. Its all about DoD devices with network access. A drone recently fed data to a network, an infected network, supposedly via USB. The drone is a sink and a source, as is the network. If one thinks strictly in terms of network devices with sink and source authority, that number dwarfs any sort of body count. Obviously, while supposedly the preponderance of DoD PCs have TPMs (and I'm inclined to think there is a lot of wiggle room in the word "most"), it is probably safe to say that essenially none of these more unconventional endpoints are so equippped. They obviously have unique identifiers just like commercial planes and such. In any event these endpoints are future markets I would think. The 2bn likely seeks to just target the more conventional endpoint as a first step. First lost laptops, later one can worry about lost tanks.
The above content is my opinion.