We have given reasons, cost and unnecessary. It's also rules creep, not to mention a spec class is about NOT having choice, it's about everybody having the same equipment.
It also sounds like you haven't yet experienced a broken ball joint. You say you worry about a wheel breaking, which has not happened yet, but not about a ball joint which would have the same effect and happens regularly. Plus, those "new" ball joints are pressed into the old aluminum arm, usually with a cheezy plastic cup. I personally would never run a late car, or at least change to early offset.