Yes, but some operations have been known to plan for attrition (the military in fact) when you have an inconsistent recruit. With low time pilots, its impossible to assure that all will adapt to the challenges of the environment (more so than those who have spent time in turbine and other commercial operations). It would not surprise me to see Eagle "overhire" by 10-20% assuming that there will be 10-20% attrition during training. In that case, there is no opportunity cost, just the cost of training.