They will in a down-turn. When things are going well however they chronically under-man their fleets and won't have any spare pilots available to go to the RAAF.
What could work is having A330 and 737 pilots trained up for surge operations. But even that would take pilots away from the airlines for a certain amount of time during the year to maintain currency in RAAF operations.
The Government would have to fund some sort of pilot surplus in the airlines to allow for this.