To most outsiders, the decision seems baffling.
After all, Ange Postecoglou did all the hard work: built a team, changed its personnel, its tactical approach and mindset and led it through two nerve-jangling play-offs to make it to the biggest sporting show on the planet.
Why step down as Socceroos coach now?
Postecoglou is a man who has always marched to the beat of a different drum, and on this occasion he is being true to his idiosyncratic self.
The demands of family life, the desire to return to club soccer, the ambition to test himself in another sphere but, more than anything, a sense of personal timing were the factors that led Postecoglou to spurn the chance to lead his nation at the World Cup in Russia next year.
"Overall, sometimes it's just an instinct, it's the right time for me, it's the right time for the team, the organisation ... for me it feels like the right time," he said as he announced, at a Sydney press conference, his decision to leave.
Clearly the impact on his family, of the constant travelling and the all-encompassing approach he brings to the job have also played a part in his decision.
"To my three boys - James, Max, Alexi - you make me smile every day and to my beautiful wife [Georgia] ... I left 24 hours after Max was born because we played Ecuador in London ... I'll never be able to repay the sacrifices she's made.
"It's been the toughest decision ... but it won't take away how rich this experience has truly been.
"Bigger things were driving me when I took this job and from that perspective I've accomplished what I wanted to do."
Nevertheless, Postecoglou will be fully aware that he will be criticised for stepping down at this point.
He knows that, alongside the bouquets, he will receive brickbats for the timing of his decision and the fact that he will not be seeing his project through to the end.
He knows he will be labelled - harshly - as a quitter, while some will accuse him of letting down not just his players, but his country.
The biggest reaction from the public will be one of incomprehension that someone could just walk away from one of the most coveted positions in world sport.
In Russia next year, there will only be 32 men on the planet experiencing the emotions, joys and frustrations of what it means to lead a nation at the World Cup.
Only a proportion of those will be people coaching their own country, and not all of them will have led their teams through the minefield that is qualifying.
All these things will undoubtedly have played across Postecoglou's mind as he came to what was evidently a gut-wrenching decision and no one knows more than he what he is giving up.
Conspiracy theories abound as to why he is quitting.
Some suggest that he fell out with the FFA hierarchy over the strategic direction of the game, that his self-appointed role as an agitator who published a manifesto for the development of the sport, called for A-League expansion and advocated promotion and relegation was too embarrassing for them.
But Postecoglou was at pains to point out in his standing-down speech that he had received total support from his employers throughout his tenure, even suggesting he had become close friends with several of the FFA staff members.
Others claim he has a lucrative job lined up overseas, while it was also argued he could no longer stand the pressure of managing the national team with the scrutiny and spotlight that come with it.
Postecoglou made clear at his press conference that he did not have a job lined up; in fact his main priority now was to take a break and spend time with his family, although he has also made no secret of the fact that he does want to coach abroad at some time and become a standard bearer for Australian coaches by securing a job in a major foreign league.
It's true that, over the course of his tenure, he has looked at different employment options. He had to, given the precarious nature of soccer management, when careers can be ended by a couple of poor results and contracts torn up, not worth the paper they are written on.
Last year, Fairfax Media reported that cashed up Chinese Super League clubs were sounding him out: it is believed he did speak to the FFA at that time, but opted to carry on in situ then while the World Cup journey was in progress.
The idea that media scrutiny and criticism made such an impact on him that he wanted to step down at this of all times is ludicrous.
This is a man who has spent more than 20 years in the coaching hot seat and is more than equipped to fight fire with fire. As he said on Wednesday, he would rather have a fight and sort things out than walk away from the job.
At this time we should perhaps take the man at face value and accept his words.
He is a complex character - part visionary, part martyr - but wholly invested in the Australian game, Australian players and the need for local players and coaches to improve, innovate and continually excel.
"I love coaching Australian players. I've often said to them when you make a choice in this country to play football ... you're choosing the hardest possible road and that takes courage, and that's why I love coaching Australian players," he said on Wednesday.
Now that he has gone, the hunt for his successor will be stepped up, and the evaluation of his period in charge will begin.
He is the first Australian-schooled coach to have led the national team to the World Cup.
He is the first Australian coach to have won a significant trophy in the men's game, when he led the Socceroos to the Asian Cup in 2015.
Just as importantly, he has sought to drive institutional change, blood new players and impose a new combative and confident mindset on the Australian team, to take the game to the opposition no matter who that is.
Some say it is foolhardy, some naive. It hasn't always worked, certainly as far as results are concerned, but Postecoglou, as he made clear on Wednesday, does not see his reign as being judged wholly by the scoreboard.
There are those who love him, and those who don't.
But no one can argue that Ange Postecoglou has not been a champion of the local game, and that he will continue to be, whether he is coaching here or overseas.
