Fair enough,
in my past life I was involved for a while in procurement as a v low level part of the blue chain - the general idea that the blue suiters knew what they wanted and were frustrated by CS and suppliers was not what I saw... I saw the suppliers making damn sure that they got their way more often than not, in a rather more determined fashion than the CS and blue were prone to behave - resistance was non-existant. It was all far too cosy, and that seemed to me to be the root cause of not getting it all sorted efficiently - I can easily imagine BAE manipulating CS/RAF by presenting a united and well drilled front, especially if you juggle the RAF around every couple of years to ensure lack of continuity.
It's basic tactics to attack an enemy where their forces meet - supplier drives in between CS and RAF, CS and RAF find they're not quite on the same hymn sheet while supplier insists it's all going great, job done - rubber stamped for another 3 months....
The bit you are wrong in, SFFP, is in your assumption that you have people who are trained in procurement and also know what they want - what you get is people who know what they want, and people who know procurement, and unfortunately they tend to think each other always has the wrong end of the stick and end up working at odds with each other.
Dave