This is pure speculation but.......
This is why I was going on about your EBA being the LAST EBA. Your executive was in the know and sold you all up the river.
Your heavy maintenance has to go somewhere other than Sydney because the Sydney real estate is just too valuable to lock up.
My paranoid guess is that what has been exercising Qantas's management brain is how to justify holding on to their Sydney-centric bias in line maintenance, while getting rid of their heavy stuff. To me, that would be a real hair-splitting act.
Both Brisbane and Melbourne have plenty of space for QF line maintenance operations - we both have oodles of land.
But of course then each of your international aircraft wouldn't have to go through Sydney to get serviced either inbound or outbound would it? And we can't have that can we?