Not to say there haven't been great innovation, but realistically most of these repairs are being made by guys that barely got out of high school, and had maybe 20 weeks of training. (I was one of them, its not a dig, its reality)
And as much as it pissed me off when a piece of equipment was no longer available, because it got shipped off, I was also equally pissed off when my unit all got sick and was throwing up because our water purification system broke, and a commander told the cooks to add bleach to the water. That is something a soldier has to do, where as a contractor wouldn't be likely to.
In the military you spend a lot of your time pissed off because someone, somewhere is doing something stupid, and it will probably get you killed.
This very succinctly sums up almost every conversation I've had with ex-military.
there is your problem.
that does not mean that the fix is to have a 'nobody can touch this but the contractors'
The US Military - all branches - have a long and great tradition of making field fixes. This is critical out there.
Waiting 3 days for a 10min fix may be acceptable in a US base, but in a war zone it will get people killed. At the very least, they need to be able to get remote support for on-site personnel to actually implement the fix.