Three defeats in the group stages did not tell the full story of Australia's tournament, as they caused Chile and Netherlands serious problems, before suffering a routine defeat to Spain.
Postecoglou believes there is a bright future for the nation despite the disappointment and hopes to have the team in a better position for the 2018 World Cup.
The head coach, who only took over in October last year, named a relatively inexperienced squad for the World Cup, the first step in his long-term plans for Australia.
"Time was the biggest enemy for me," Postecoglou is quoted as saying to ABC.
"I was trying to do a lot in a short space of time and I didn't, right from the start, want to discount this World Cup as some sort of building exercise of experimentation.
"It was a lot of change in a short space of time. Now we can work, I think, a bit more methodically.
"In four years' time, the ideal for me is to qualify obviously for the World Cup (in Russia), but not be ranked 60 (actually 62nd) in the world, and not to have just one player playing in the top leagues.
"(We need) to improve our results starting with our own region in Asia in the Asian Cup.
"Improve results, get our ranking up and then by the time the next World Cup comes along, (the aim) is to have hopefully half a dozen players playing in the top leagues around the world."
Australia will host the 2015 Asian Cup in January.
‘After Manchester City’s recent form, maybe they’re the underdogs against Manchester United!’ Former Red Devils defender on this weekend’s derby
‘Arteta, Alonso, Emery, me… none of us were physical players – we needed the understanding of the game. That probably helped us move into management’: Premier League boss reveals reasons for natural career progression
