Isnt the issue with the C17 really now availability of airframes, seeing the need for such has been pointed out by the services themselves, and we now have the funds to do so?
The availability of sound C-17 airframes is the issue. They would have to be used and go through a convoluted FMS process. Both of those issues are not insurmountable but are difficult.
What we know of is that 16 airframes last month got given the deactivation status from UASF front-line to back-up reserve status. This means that their is an expectation that they could go back into service via rotation to plug any operational gaps such as when aircraft head through depot.
Eight airframes from 10 Airlift Sqd at McChord and another eight from 17th Airlift Sqd at Charleston S.C have been pulled. I believe that the Charleston airframes were particularly old being amongst the first C-17 builds with 91-95 serial tails. Their most timed airframe has hit over 20000 hours and is 25 years old. I understand the McChord tails are somewhat younger but still fairly old with 96-99 serial tails and I would assume they are the ones which were be pulled from the flight line first as 10 Sqd was deactivated. I have not seen what serial tails 10 Sqd were flying.
USAF now has an expectation that the C-17 will stay in service to 42000 hours beyond the original 30000 hours. The bulk of C-17 fleet have flown between 11000-15000 hours. The early block builds are in the high teens. The average C-17 historically has flown 800 hours pa. However some years, some airframes have been given in excess of 1000 hours.
The DoD considers that it has more than ample Strategic Airlift in its force structure mix. It has more airworthy C-17's & C-5's than it can fund. Congress has loved building them in marginal congressional districts across the 30 states were component manufacturing was in place. However, Congress has never been too keen on operating them. I would not be surprised to see another couple of CONUS C-17 Squadrons deactivated over the next few years.
The next political gravy train will be the C-17 MLU which will create lots of further work in marginal Congressional districts next decade. No announcement about this as yet but it is about as certain a thing as the tide coming in.