NZ is an end of the line carrier much like QF is. However, they seem to be successful because:
1. They have a 80% share of their domestic market
2. They only fly international routes where they have a monopoly; or
3. If they don't have a monopoly on the international route the fly in, they operate joint ventures with a dominant player on the route. That is, CX to HKG, NH to NRT, VA to Australia and soon SQ to SIN. They made it clear they won't fly to SIN if the alliance with SQ was not approved