Green Flash, nicely put. When I first read your post I thought I was in for one of the tunnel stories.
That is a difference from WW2 as well. There the captive was only a few hundred miles from home on the same continent with a physical appearance similar to his captors. In Vietnam the escapee or evader was at a slight disadvantage to quote "at 6ft 2in and 220lbs I looked a little different from the little yellow slope eyed bastards."
In Vietnam there was also a degree of tactical intelligence that was not time critical and hence worth preserving. In Afg the information would be very time critical. In Iraq it would simply be jump into an orange suit and lose your head - if you had time to change
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The Big 3 and then Big 4 were for POW in conventional, symetric warfare. One of the POW in the Falklands War (I won't mention his name) had not had RTI training despite being in a prone to capture job. Nor had he assimilated all the available war films. He was 'interrogated' subtly by an expert who passed himself off as an aircrew mate and extracted rather more information than he would had he used strong arm tactics. The Big 4 would have been appropriate in this case but he had not been trained.