The company could have 40-odd years of return on its investment if people were happy where they were. As for the 'test of resolve', they're not applying to join a monastery.
I don't see any need for centrally coordinated recruitment, at least not for regional airports.
Unit identifies upcoming vacancy -> Unit recruits someone, perhaps one of the assistants at that unit -> Unit books that person onto the next available Basic & ADI course at CATC or Cwmbran.