The problem with trying to save $ by using contractors or GS is that at the end of the day the deltas between the different choices aren't that much. The upside of using CTRs is that you can stop paying them when the work goes away, they're easy to turn on in a pinch, and they show up qualified. Less so for Mil and GS. The problem is that there's essentially a set market price for specific skill sets. Aviators with instructor experience, 1000+hrs, and whatever other requirements end up in that SOW or PD are going to cost a certain amount. If you go cheaper you're not going to get guys with the same skill set.
If the military goes to more civilians for ancillary type flying the concern is going to be saving manning more so than $$$. In typical fashion they'll legitimize extra expense as being "cheaper in the short term" and always having the ability to shut it off.
When looking at market economics the Air Force is already noticing that they're having problems filling their GS positions because their pay isn't competitive compared to the airlines so they're starting to push iniatives to increase them for those positions.
On the contractor side of the house, the company goes to the customer and says they're having retention issues and they're going to have to start paying more fix them. Customer has the option of saying no, or yes... if it's something deemed critical the answer is typically yes. Rise and repeat. There are some projects right now where companies are projecting they'll need to increase pay by 20-25% and pay their folks $1000/ day to keep them from bailing for the airlines. In Iraq back in its heyday, companies were paying pilots $2000/ day to meet demand for qualified personnel. I don't expect them to pay nearly that much for a domestic gig but if it comes between paying enough to staff a contract and losing a profitable contract, a Contractor is going to adjust its pay/benefits package to keep manning up to keep the contract.