Been widely commented on in the past, and I think history has ultimately shown it was the wrong decision, however.

1. Fleet complexity - big focus by QF over a number of years to minimise number of types in fleet.

2. More suitable aircraft for its core routes - A380 better choice for long routes ie SYD/MEL-LHR/LAX that are slot/window restricted - so long as you can fill it. Arguably A330 better aircraft for the shorter 6-8hr hops into Asia.

3. Dreamliner effect - When QF made the decision not to go with 777, don't think it was forecast that the 787s would be so delayed or have so many problems

4. Depreciation policy - Australian taxation policies make it less effective for QF to roll its fleet as quickly as others.

As it stands the 777 is now getting long in the tooth, and I would think QF would be better getting early deliveries of A350/777-X to replace the last 9 of its 747s which is probably a 2018-2020 timeframe.