Let's not forget that if you're an AU based passenger who may fly a mix of domestic and international routes the choices are, for most, down to two. QF and partners or VA and partners. Sure, if you mostly fly international out of a major city then you could fly just about anyone depending on where you go, but for people who have choices and want to stay with the one group for FF loyalty purposes, or indeed perhaps contracted to for work travel, then you're down to two. It's not like the USA where there's far more competition, in most cities, betwwen the big 3 legacy carriers(AA,DL,UA) the big LCC's(WN,NK,F9) and the others (AS,B6) and any number of smaller carriers filling more niche roles. Nor is it like just about anywhere in Europe or Asia where you have dozens of options, both legacy and LCC to get you from one part to the next, usully direct. These are all factors that should be taken into account imo. Australia is more akin to Canada - if you want to get from YYZ to YUL it's going to be AC or WS and even if AA and Dl fly to both, you're less likely to go to either of those carriers even if you think AC sucks(which many in Canada do)