I think you VASTLY underestimate the size of US Armed Forces in terms of what's required for authentication, authorization, and access control. US DOD has well

I think you VASTLY underestimate the size of US Armed Forces in terms of what's required for authentication, authorization, and access control. US DOD has well over 4 million Active Duty, Civilian Employees, Contractors, etc. Though numbers are hard to pin down, since the number of contractors is in many cases not what is being paid for by the contract (e.g. firm-fixed price, and service based contracts like IDIQ which the contract holder dedicates cleared staff, but otherwise it's hard to know; compared to time-and-material/"butts-in-seats" where numbers are know by the Government per contract). The US DOD attempted to move everything to MS AD at one point but hit a limitation in the number of objects AD let's you create (~2bn).