Yes, it would take probably about 5 years for the military to "get it's money's worth" out of a recruit.
That's about what they said when I was regular Army. When somebody enlists for just two or three years and then gets out, the Army actually loses money. Factoring in the expense of training, housing, feeding, clothing, providing ammunition, medical care, and other costs.
Waaay back when I entered the USN, in order to participate in the Nuclear Power Program, one had to enlist for 6 years active duty. This is because it took about 1.5 to 2 years of training before you ever reached a ship. Once you reached a submarine, it took about another year to be fully qualified on all watchstations and in submarines. That is also why they used to offer a $35,000 bonus to re-enlist.
So yes, it does take some time for the military to break even on how much they spend to train you vs. how much time they get to use your services.
Besides, this entire argument about drafting is bogus. If you watch "Around the Services" on the Military Channel on occasion, you will note the month after month, they report the various services all meet their recruitment goals. There is no need for the draft.
We have far too many people who wish not to contribute or serve in any capicity and at some point we will be hiring outside of country to fill our military and that is now done in some minor form.
they even threatened the use of nuclear weapons.
Quite probably true. However, if we had used WWII level technology and training, I would think we would also use WWII level tactics as well. And WWII level tactics include total war and nuclear bombs! Somehow I think carpet bombing of Iraqi cities or the use of Hiroshima size nuclear bombs would have led to our defeat at the hands of Saddam's military, or the "insurgents" either.If we'd tried to take down Iraq in 1991 or 2003 with WWII level technology and training, we would have had MUCH higher casualties.