The ultimate test would be to take a sample of say, 100 of Captain Collins' colleagues at the time, have them each perform this particular flight under the exact same circumstances and observe the outcome.
If the crash result was repeated by even one, then statistically it could be argued that the cause was primarily systemic and environmental factors.
My point being that this Captain's training, beliefs and ability represented the average, or even above average, Air NZ pilot of the time. If this assumption is correct then it is not useful to accident avoidance simply argue pilot error when other factors have aligned to overwhelm an 'average' pilot.
Of course we can't actually conduct such an experiment, what with the expense and loss of life etc. But those of us who are approaching the end of our careers without incident should probably acknowledge an element of good luck!