Re: What will happen during a war?
The spare parts inventory software has already had a meltdown so you don't really need a war to get into this situation.
I think they they're an updated version of the German Panzer problem from WW2. The Germans designed some incredibly fine tanks, difficult to destroy, powerfully armed and so on. Unfortunately they over-improved them, resulting in fighting vehicles that were expensive to produce and difficult to mass produce. (They also had other problems like forgetting to make the things narrow enough to fit on railway freight cars.) There were never enough of them but there were always a lot of T-34s and as they say, the T34 only needs to get lucky once while the Panzer needed to get lucky 100% of the time.
Since the US defense sector is now a major component of the economy I daresay their real reason for existing is a form of tribute from vassal states.