Earlier quoted context omitted.
"Lifetime buys" are a thing, and also can be expensive because you don't always have a good estimate when doing so. Either you buy too many and waste $ with excess stock, or you don't buy enough then 10 years later have to scrounge for more stock at higher prices, or come up with a replacement. It's a tough problem.
Let's assume we actually get 50 Virginia class submarines (whims of Congress, and all that). Let's assume we need on average 3 controllers per year. That's a total of 5,000 XBox controller. At $20 a piece, the pentagon has now spent $10,000. This is not what in military spending passes for excess $ :) Yes, the numbers might be somewhat off, and there's storage cost, but really - we're talking Pentagon here. The place…
I think when its come to HIDs like controllers or keyboards, off the shelf is fine. We can have the exact same conversation for Dell keyboards or 3rd party keyboards and mice.