Charun

I think they could not afford the needed time to retrain pilots. Frontier mainly used Ghost Drones, and the VF-171 forces where an afterthought with on average little experience or training. So they already had a pilot shortage, meaning that not making VF-25's but instead rapidly pushing out a new VF-171 variant made the most sense. No precious pilots taken away from active duty to learn to fly a totally new plane, instead they just shoved pilots into an improved VF-171 where the training took only a fraction of the time. Plus the fold quartz got used to build weapons. In the end even the basic bullets of a mook VF-171 used fold quartz. Frontier used an absolute fortune of fold quartz as nothing but standard ammo.