The latest research suggests that cot death is a delayed letting go of a particular womb reflex (don't know name sorry).
Reflexes are involuntary physical responses to stimulus, certain ones such as Moro reflex or Plantar grasp, exist in infants at certain ages but disappear as baby's body system matures, usually at a typical age.
In the womb there is a reflex of the lungs which is there to protect the foetus. When the foetus is mature enough it will start to practice exercising its lungs, in preparation for birth. The activity is not necessary for life however, so if for any reason the oxygen levels go down (due to mothers activity, position, pressure on cord etc), the foetus will cease 'breathing' in order to conserve the available oxygen for vital life functions instead.
This reflex should disappear at birth, the disappearance triggered by birth hormones etc. However in some babies it is thought it does not and disappears later (varying in when). It is thought that all babies have lost this reflex by 1yo which is why the risk of cot death goes down drastically at this age.
If the baby still has this reflex, anything which causes oxygen levels to fall will make baby stop breathing. Which is why there are so many factors which are linked to cot death. All the factors are associated with reduction in oxygen - smoking; airway partially blocked by being face down, etc etc.
So the cot death baby is different to you or I in that if it can't breathe fully, instead of fighting for breath, it actually stops instead.
Of course, there may be some other physical characteristics which are associated with delayed reflex disappearance, perhaps the hearing disorder thing which Jumping mentions would be one.
So the understanding around cot death causes is developing, and this is why it is highly unlikely the recommendations are going to go backwards.