QAN is issuing refunds to some passengers, as many are not happy to merely obtain a travel credit and keep pushing (over a few months) to receive a refund. There's one complaint in the 'SMH' travel section from Saturday 20 November.
Not all larger aircraft are in 'the desert' as you claim. For instance the A330-200s are not: Last I looked it up, some are at Avalon Airport in Victoria, and others in Sydney and Brisbane. Mechanics are needed to perform tasks such as regularly moving aircraft to rotate tyres.
A Bloomberg article said in part:
Aircraft can’t simply be dusted back into action. They need plenty of work and attention while in storage, from maintenance of hydraulics and flight-control systems to protection against insects and wildlife – nesting birds can be a problem.
Then there’s humidity, which can corrode parts and damage interiors. Even when parked on runways, planes are often loaded with fuel to keep them from rocking in the wind and to ensure tanks stay lubricated.
and:
Etihad Airways said its engineers are working around the clock maintaining its grounded fleet, a process that includes running engines and powering up aircraft, checking flight controls, and covering sensors and engines to protect inner workings from sand and dust.
(20min delay)