KG is a very high yielding business route with lots of cashed up miners with tax free dollars.
A few half truths and some completely erroneous statements.
No mining is now tax free, gold was but the Hawke Keating administration stopped that so now with state government royalties there is actually double taxation.
Far less miners than there used to be, modernisation. Anyway most of the punters were not miners but exploration people and as a result of taxation, native title and in real terms depressed metal prices these people are now to be found in Africa or South America.
A few hundred bucks for the one hour trip won't hurt their pocket.
Nowadays the mix of paxs is very similar to on any other flight. I've lived and worked in Kal for over 20 years and so normally know a fair few of my fellow travellers.
The KG route is a bit like a suburban commuter train, 100% load one way 35% on the return if your are lucky. recently I have been 1 of 9 in a Skywest F50 when the QF 146 had 7 paxs and 1 of 13 when Skywest no had competing service. Each of these had a good load into Kal. So it would not suit a Virgin type low yield operation needing a good load in both directions
Historically there has never been many discounted fares on this route it was a case of supply and demand. Pay up and be there in an hour, 600k of petrol and wear and tear (plus a few radar checks ..... viz the old Skywest advert), 61/2 hours on the bus, 8 ½ on the train (no more nightly sleepers), your choice. that's why its high yield route not much choice.
Using a 737? AN had used one on this route for quite a few years now so its only logical that now QF link will do so when they have one available. 1 737 must make more sense than 2 146s. Like everywhere else the loads are down, on a Mon. morning AN had a 737 and a 146 with a QF 146 and a follow-up 146 for ADL which did not have enough through paxs and was withdrawn, now you've got 2x146 & a F50.. Now if one of those 146s is returning near empty a 737 is better. Skywest use the F 50 onto Laverton or Leonora.