The military way! Throw more money at the turkey!
The Marine Corps and the Air Force pay a fixed amount per flight hour, and it is Rolls Royce's problem to make sure the engines are working.
Rolls doesn't want to renew the contracts when they expire, because the engine is not lasting as long as expected, so they're losing money on the deal.
If Rolls doesn't wish to either renew the maintenance contracts or redesign the compressor stages that are wearing out prematurely, then it is prudent to find another engine source. The alternative is for the operators to take on all maintance costs themselves.
Pratt and Whitney Canada is pretty good at making gas turbines...