Another issue is currency. If somebody flies very infrequently, they will be at best in the 'concious competence' state, that is they will have to think about something then do it. If they have got themselves into a situation, that split second might be just too long.
There is also fixation on task. When somebody is overloaded mentally they will tend to focus on one issue to the detriment of all else that is happening. I remember a presumably fairly new helicopter pilot calling up to say that he was encountering lowering cloud, reducing visibility, couldn't turn around due to high ground and sounding very worried. The also newish ATCO tried to identify him on radar by asking radial and DME. I leant across and said "he is in a bloody helicopter - tell him to find a safe place, check for wires and put it on the ground". The pilot's reply was "can I do that?". He was so focussed on the weather problem he forgot the obvious.