I am not defending AJ because many of my friends, and I, cannot stand his advocacy re social issues. I have no interest in rugby and wouldn't even know if the chap who got himself into hot water with an Instagram post plays 'league' or 'union', but his silencing by Qantas (as a sponsor) and others ignored what democracy is all about. (It's OK for the Left to say and do what they like, but for anyone conservative or religious...nup).
That said, if one examines the BITRE figures, QFi's (i.e. international 'mainline') share of overall passengers has been increasing a bit (excluding JQ), due to new or recommenced routes. YVR seasonally, increases in frequency to MNL, NRT and others, QFi flying SYD and MEL-DPS and so on are a few small examples.
However on some historically important routes, such as MEL/SYD-LHR, 2 x A388s daily each way have been reduced to 1 x A388/ 1 x B789 daily each way.
There's a heck of a lot more competition on Oz-USA than even five years ago, so in a stagnant or slightly declining number of seats sold situation as has been the case on these routes in the past year, yields are highly likely to have suffered.
jb747's explanation may well be on the money.
What would be fascinating, and not just for QF, would be if airline insiders leaked spreadsheets or other documents showing which individual routes were profitable or lossmaking during each financial year, and by how much. There'd have to be sensible allocation (perhaps by revenue passenger kilometres) of corporate and other overheads.