QANTAS didn't survey its passengers to make this decision. Had they asked the recurring business flyer, I suspect the signal would have been different, even if the economic decision was to walk.
I am a frequent QANTAS passenger. I know from all my experiences and peers discussions, we prefer the 380 over almost any shell QANTAS flies.
I flew the original QANTAS 747 longhauls. They were fine for their day. They are significantly behind the ball compared to the 380 experience. The 350 will be a fine plane. the 787 is a compromised experience in the air.
(btw, it is QANTAS not Quantas: Its an Acronym)