Within the regional airline landscape the smaller regionals (with say 1 to 5 aircraft) cannot achieve the same level of efficiencies as the likes of Rex that operte around 50 aircraft.
QantasLink also would have reasonable efficiencies (in the context of regional) and they also have the added benefit of their results being somewhat hidden within the broader Qantas Group results. This helps with the secret squirrel factor...
Agree with a lot of the points raised earlier about the regionals simply not having the same efficiencies as domestic / low cost carriers, but then within the regionals there are also vast differences with economies of scale.
Airlines such as Rex have a diverse network and can spread overheads across a lot of activity, where they can sustain a loss on a route in an attempt to make it work in the longer term. For a smaller regional this can be impossible and can lead to the airline collapsing. (i.e. varying depths of pockets)
It is certainly an interesting topic and will be interesting to see how the next 5 to 10 years evolve.