They’re fully written down. The only ‘cost’ of them now is how much it takes to get them back flying again.
If there is demand in a couple of years, they’ll return in line with demand. If demand is still subdued then they won’t. Pretty simple really.
The only real crystal ball gazing in this equation is will demand return on SYD-LAX, MEL-LAX, SIN-LHR to justify an A380. I reckon in 2-3 years time the demand will be there. That’s six jets right there.
Of course, where does the A350 fit into this? Who freaking knows. May end up running a 787 between SIN and LHR whilst an A350 goes direct from the east coast. The Kangaroo route is the only one that I can see is complicated by the A350. LAX certainly isn’t given the proposed config of the ULH A350s QF is considering.
Though even something like ADL-LAX could become a thing for a 787 or A350 given the config- probably the 787 given the A350 is supposed to have P/C and I can’t see there being demand for that out of ADL. Perhaps SYD-LAS an option for a 240ish seater as well. The only thing that would see the A380 not return is if QF decide to increase hull numbers and go point to point into some of these secondary routes.