"we were lectured that a soldier was supposed to retain more or less full combat efficiency for a period of 7-10 days on 1 1/2 to 2 hours"

I have a hard time comprehending this. Generally speaking, after 2 days with the sleep that you speak of, even with proper nutrients and hydration; the body begins it's process of microsleeps. As soon as this begins, combat efficiency and effectiveness is most definitely not full. This subject is definitely going to be brought up in the future as military budgets get tighter and tighter, units are going to be forced to get the bang for the buck.

Effective combat should always contain an element and concept of swift rotations. We learned this after Vietnam.