To put things in simplistic terms, since privatisation the share price of QAN showed consistent long term growth and consistent healthy dividends until the mid 2000's. Qantas was a blue chip share.
This despite Asian finical crisis, Bird flu, Sept '11 (coinciding with Ansett demise admittedly).
What happened in the mid 2000's?
Jetstar was launched in 2004.
Qantas management are the only full service carrier that has successfully launched a LCC that has not cannibalised it's parent. Profitable every year since inception. (well that's what we are supposed to believe)
If someone were to produce a simple graph of profitability (QF Group) and share price since privatisation (ignoring the share spike due takeover bid of 2008). Plot this graph with the proliferation of Jetstar aircraft shown on the timescale.
We may well see why all other full service carriers have abandoned this strategy.