Maybe this is the problem. Too much government red tape.
While, it seems like a lot of red tape, is it really about them covering their asses. If you get injured (to the point of being non deployable) while in the military, they do what they can to keep you in (if you're not a total fuck up, which means basically just showing up when you're supposed to) or get you out with some benefits. Most of the time, the member themselves doesn't want to get out and the higher ups will try and fight for them to have different duties or being in a different position to allow them to continue their career. Most of the time, I think it comes down to them just not being eligible for reenlistment and are able to finish their contracts honorably.
And, even then, if you have documented medical problems which occurred while in military service, the VA will give you disability of a varying amount.