That’s all fine, but the point is that in a multi-year peer war, after year one, NCOs with “years of training” will all be gone, and the NCOs who take over will have weeks or months of training.
If your basic force structure relies on NCOs with “years of training” and you don’t have any, you have to change your basic defence strategy in the middle of a war, on the fly.
Better to be realistic and set things up before hand.
This happens in every war the US has faced. You have a general cadre of Regular officers and NCO’s, who then train the citizen-soldiers to become officers and NCO’s. Often these troops perform much better in combat than the cadre because they were baptized by fire, and learned teh ways to survive
You had 6-8 weeks of BNOC to make Staff, 6-8 weeks of ANOC to make SFC.
Not necessarily "years and years" of training.