I wonder if the Marine Corps uses retired Snipers as primary instructors in it's precision shooting courses, and if not, would this alleviate the problem?
If you are talking about PMI's, this billet is filled by NCO's, and if I am not mistaken even an occasional LCpl, under certain circumstances. Just the same, this is for Marine Corps basic rifle skills training, not "precision" shooting, per se; routine range qualification and ongoing training in the grunts. I don't think the Corps is lacking in its basic marksmanship, as this the very heart and soul of the Corps. We have "expert" qualified riflemen that cook, and drive trucks, and splice wires, and talk on phones, and can make head-shots at 500 yards with iron sights.
As for "precision" courses, I have no idea what the practice is for SS School. Some of the Snipers here can address that if they choose.