GB, with respect, in QF ops the
A380 (all 4 class config.) carries 48% more passengers (450) than a
QF B744 in 4 class config. (307)
The 744 doesn't even come close. The
A380 has 50% more floor space than a 744, so whichever config. is chosen the 380 will fit approx 50% more passengers when comparing apples with apples.
When and if the bean counters ever get around to matching the A380 seat plan to what the market really wants. ie. more econ and premium econ, the difference will be even greater.
As for 773's, no doubt they would be good, but do the numbers on LAX-MEL and the tripler comes out pretty poorly.