The money earner really is in the golden triangle with the business market and they will always be prepared to pay top dollar so long as they are recognised in the business lounge,on board and with on time departures...they don't want to fly on a airborne version of a bus.
Wasn't an all business class airline tried recently in Australia and didn't last long ? OZJET
Silverjet in the UK, also all business class folded just over a year ago.
Even Singapore Airlines have had to suspend some of their all business class A340 services to New York. Generally the premium cabins on all flights have had disappointing loads.
Jetstar Asia have a corporate travel department with a growing list of clients, catering to downgraders.
Even the Brisbane - Melbourne leg of the golden triangle is only a little over two hours long. With business fares at around $1300 return and "e-deals" from $170, the corporate world is going to find it difficult to justify the extra expense to the share holders at the moment. Many contracts allow business class on flights longer than eight hours only.
A $1000+ saving is difficult to ignore when the travel budget comes under the microscope. Of course the politicians and top end of town will pay, but will that be enough to justify the cost of keeping business class going ? First Class has all but disappeared on short flights throughout the world. Prehaps Business class will be restricted to a few of the more desirable seats ie front row or exit, flexible ticket, increased baggage allowance and a better meal.