All QF LH FO's have a command endorsement on the type they operate. It allows QF to cheaply fly heavy crews with one captain instead of the two that other airlines use.
Qantas isn't losing FO's, they are losing experienced cruise captains paid at an FO rate.
Other airlines, short of experienced captains are starting to look long and hard at the huge reserve of experience, and the heavy metal command endorsements that these pilots have.
Memo Qantas management: If you are waiting for a bunch of captains to leave before you do anything.... it's already happening.