If you want "informed" comment, that's commercial in confidence..
That said, yes, sure, a lot of 9's out there looking at various rabdom dates in zjuly for MEL/SYD/BNE - but not all. I saw some A4's and more limited I and W inventory on some sectors.
Some "experienced" points to keep in mind.
1. EF shows what they will sell in one transaction.
2. These flights all have return sectors to fly with bookings. Lower loads(maybe) may not equate to lower loads on the return. Plus we're talking flights carrying hundreds of pax each way.
3. They also carry cargo
I fully understand the REAL question here is "Do QF consolidate flights for international - specifically USA - as (it is alleged) they do on domestic, and if so what are the chances the flights I am booked on will get cancelled and chance to retain J seats if so?"
I really do not think this is a thing. It's not like the next flight is in 30mins or an hour, and potentially hundreds of pax (including return sectors) affected would probably cost more than anything saved due to a "consolidation cancel"
The reality us that operational reliability ussues are more than likely a far bigger thing to worry about than potential flight consolidation.
This view may not be as "informed" as you would like, but anyone in the actual know almost certainly is not going to post on a public forum.