I do not know the numbers but dare to say with great certainty that regular vocational training is orders of magnitude more efficient and thus lower in cost than the military.

The vocational training argument is used quite a bit by military recruiters, but the reality is little of that training is valued on the job market, with a few exceptions. There are companies that do have veteran hiring preferences, but these are often social and economic justice efforts and do not take into account any actual skills.