New pilots are years from collecting retirement, and in all likelihood, years from producing high medical bills. Throw out your Majs and Lt Cols at 12-15, you don't have to pay them retirement, and meanwhile you've got a crop of brand new 2Lts making half the paycheck and who are thrilled to be there.
I think the point is, while 600 people attempted to VSP, and while those of us who are in like to think that this option can't possibly be real because it will hurt the manning too badly, the truth is there are plenty of young bucks out there who would jump at the chance to fly a C-17, B-1, F-16, F-35...you name it, for half of what we're making now.