Ascoteer.
You are making the same mistake that manning is making. You assume that because the airlines don't want FJ pilots there is no demand for them in civvy street. That is wrong. There are hundreds of jobs for FJ pilots in civvy street just not necessarily in the airlines. Aerospace companies and Middle Eastern AirForces currently pay far more than the airlines do and they are lapping up FJ pilots for flying and ground based roles.
Also you make the mistake of thinking basic salary is everything. Once you add in virtual pension contributions and money available for schooling the military pay package actually stacks up pretty nicely against the airlines at least. As a PAS Flt Lt with 3 kids my basic salary may be less than an airline pilot but I don't make pension contributions and I don't pay a penny for private schooling. That's before I even factor in what I can earn as a QFI on secondment.
So I agree that Multi Engine pilots are in high demand and can therefore justify being paid more but don't presume the same isn't true for FJ pilots. I dare say a Rotary expert could make the same case for his brethren too.
BV