From 1984 to 1993, Ange Postecoglou played 193 times for South Melbourne and coached the club from 1996 to 2000. He was key to FIFA recognition that South Melbourne was Oceania's best club of the 20th century with twice as many evaluation points as second placed Sydney City. Ange won two national titles as a player and two as a coach.
From there Ange coached the Socceroo under 20s from 2000 to 2007. Coaching the U20s is difficult, some countries put a lot of resources behind their teams, e.g. in Asia South and North Korea. Australia doesn't have that type of resources. Therefore, Australian U20s coach mandate is participating in as many tournaments as possible, and finding and developing potential Socceroos. And Ange's win-loss record looks good compared to more recent Dutch coaches. However, there were critics, SBS and Craig Foster most notably (you can probably find the youtube video).
In 2008, he spend around 9 months as coach of Greek team Panachaiki. Again he may have felt he wasn't judged fairly.
On his return to Australia, Ange would have been keep to return to the top of Australian coaching and an A-League contract. Melbourne Heart was the opportunity. However, there was a feeling that Heart was to be distanced from South Melbourne (and old Soccer). It is understood that the appointed coach, Johannes van't Schip, was offered Ange as his assistant. Schip hesitated. Schip wanted to link up with a former team mate (they played together in the early 1980s) from Ajax - Jesper Olsen. Olsen was already living in Victoria and had some involvement in the local soccer community. Offered an additional Australian assistant (to do their part training the next generation of coaches?), Schip now chose legendary Australian player Ante Milicic who had recently become coach of Sydney United in the NSW Premier league.
Ange had to wait. And the Roar provided, albeit with a move away from family to a region where his feats where not known. And to replace a local hero.
So, Brisbane's domination of Heart must have provided special satisfaction for Ange. But he didn't say so. He wouldn't. And didn't need to.