Going Boeing:
who is to say JQ salaries in NZ will be more? If JQ use a NZ AOC then it might be logical that JC will become branded JQ?? instead of QF....so my point still stands for now at least. Lets keep in the mind the cost of the operating crew only is a small percentage of the cost of operating a flight...nothing near for example fuel burn...not to mention 10-15% more capacity.
You also cant compare people travelling on a INT sector (of 7 hours) to connect to another flight (as your example in SIN) to a straight domestic short haul feeder service. In OZ thousands of passengers every day connect to QF and other full service INT flights using JQ & DJ domestic flights. Plus in NZ there is no full service domestic to compete with...so no diff.