Why would you fly SYD/HNL/SFO on a "classic"when you can fly SYD/AKL/SFO on a 400.
Maybe QF want to get their hands on some SFO slots to utilise in the future, when the 773ERs come on-line. SQ will get Pacific rights at some stage and fragmentation will occur. Time to get back into SFO and prepare for competition/fragmentation.