In any modern army you'll be taught that incapacitated enemies are the best ones since they take up more of the enemies ressources than dead ones.
Also, as an Afghanistan veteran I can assure you that the 5.56 has more than enough power as you hardly have engagement ranges beyond 200 m.
See, the funny thing about this is that I was just reading an article this morning from ... I think it was Army Times? Can't remember. Anyway, they said that >50% of the firefights in Trashcanistan were 500 yards plus.
So, not saying that your numbers are necessarily off, but what's the sample size you're using to base your statistic of "hardly any" on? Personal observation? Stories from buddies?