With the likes of Flair (777 partners) Southwest and Ryanair…
1. Look at their catchment, the population base available to them. Europe 749 million people. USA 332 million people. London alone is around 14 million people, half the Australian population.
2. Ryanair uses secondary airports to reduce costs. Girona for Barcelona, Stanstead for London, Beauvais for Paris etc. I do not know about the other two.
Neither of these points apply in the Australian market. Tony Fernandez spoke wise words about entering the Australian market.