Rex's cost are much lower (aircrafr/crew etc). Nothing special at all about qantas. Jetstar doesn't include a checked bag & has terrible reputation with any disruption. Think Rex's loads are improving. Qantas's aren't that special SYD/MEL.I just don't see why Rex would be successful in the long term while so many airlines haven't been. Tiger is dust and tried from the cheap end and Virgin is back to half its former self, even after trying so hard and for so long to woo lucrative corporate clients with a presumed equal to Qantas product. I personally never believed the latter and my few experiences on them were proof for that (childish and unprofessional crew, mediocre catering, having to use the Bogan terminal in Sydney and so on...) but at least for a while, they seemed to be quite successful in their efforts.
So why Rex? The brand is mostly known to country folks (and by quite many of them loathed rather than loved, I may add) who won't be the ones saving the airline on the main city routes. And both Qantas and Virgin will just start dumping cheaper fares on those routes (they're doing it already, actually) which might be sustainable for them (Qantas, at least) but will not help Rex. Top this off with not being member fo any loyalty program, it really leaves the cheap ticket crowd- and they already got Jetstar!
Maybe I am too pessimistic but I can't help but getting the feeling that the whole idea is doomed from the start. Rex has the word "regional" in its name and probably should stick to it rather than following grand dreams that will fail, sooner or later. I might be wrong of course, who knows.