Perhaps we could take it at face value when Delta says they are going down to 6 times weekly on LAX-SYD. A quick look at the Delta fleet list shows only 5 777-200LR in the fleet and only 8 777-200ERs. They could use some 747s which NW operate, but the 777 is the type they want to operate to SYD.
I wonder if people want to travel on the day that Delta is not operating, whether they will offer the V Australia service for that day. V Australia would probably like them to put passengers on SYD-BNE-LAX to help loads on the BNE-LAX flight, if the Delta clients do not mind changing planes at BNE.