I'm sure it's been looked at. The airlines simply look at how much traffic (or people) are booking flights between ADL and LST (via MEL). If there is enough traffic to justify a direct service, they would do it. Clearly, right now, there isn't enough demand to fill 100 seater jet.

B737-800 VH-VXS returned to service today after a more than 12 month hiatus, operating QF539 BNE SYD.

With B738 VH-VXS back in service this leaves only VXH still to return to service with QANTAS after its cancelled flight QF536 on 24/5/21.
It looks as though VXS operated a very late QF718 leaving BNE at 1:12 and arriving at CNS at 3:20 this morning, over five hours late. It was probably a replacement aircraft for the flight and needed to be in CNS to operate the first flight back to BNE this morning at 6:00.

The crew to operate the CNS service were late ex CBR due to a breakdown and aircraft swap.

A332 VH-EBR flew from SYD to BNE on 8/6/21 as QF6122 for maintenance. Possibly pre-return to service maintenance.

B738 VH-VXH conducted a 38 minute test flight from and back to BNE this morning, 20/6/21 as QF6127. Hopefully, a return to service is not too far away.

A380 VH-OQC has been undergoing maintenance in LAX since relocating from VCV on 20/5/21. It conducted an extensive 87 minute test flight from LAX on 18/6/21 and is shortly due to ferry to DRS for further maintenance.

VH-VXH returned to service this morning operating QF1076 from BNE to ISA. This means that all B738s have now returned to service since the aircraft groundings and storage brought about by COVID.

A380 VH-OQC has defied us all by flying from LAX to AUH, not DRS, for further maintenance arriving late last night, 21/6/21 local time.

A332 VH-EBG returned to service on 28/6/21 when it operated a return flight BNE - DRW. This leaves only seven non-active QANTAS A332s: VH-EBA, EBB, EBD, EBN, EBO, EBR & EBV.