Four years ago, few people had heard of Scott Sio, Scott Fardy or Bernard Foley. So who will emerge as the key Wallabies in 2019? Chris Dutton finds out.
Flexible contracts, overseas-based Wallabies and veterans nearing the end of their careers - it's a step into the unknown after the World Cup as Australian rugby enters a new era.
The Wallabies played New Zealand in the World Cup final a year after coach Michael Cheika took the reins and overhauled Australian rugby.
But what will his team look like for the 2019 World Cup and everything in between? 
Will Adam Ashley-Cooper continue his Test career, will Matt Giteau and Drew Mitchell play on, will Quade Cooper ever wear Wallabies gold again? Those are just some of the questions Cheika faces as he continues his five-year contract to rebuild the Wallabies and take them to the next World Cup in Japan.
The challenge is trying to unearth new stars that we've never heard of. Four years ago no one knew of Scott Sio, Sam Carter, Will Skelton, Scott Fardy, Sean McMahon, Bernard Foley or Tevita Kuridrani.
Former Test coach John Connolly says Australia must manage its development pathways and ensure they blood enough young talent to replace the experience that may not be around in four years.
"Australia has to get the balance right, don't break the bank," Connolly says. "You've got to develop players. Scott Fardy's a perfect example. He slipped through the net and made his Test debut at 28 years old. It's all about balance and putting time into those players coming through."
PROPS:
World Cup squad: Scott Sio, Toby Smith, James Slipper, Greg Holmes, Sekope Kepu.
2019 prospects: Paul Alo-Emile, Tetera Faulkner, Allan Alaalatoa.
The good news for the Wallabies is that Holmes is the only prop in the World Cup squad who is on the wrong side of 30. The Wallabies have built scrum respect under Argentina great Mario Ledesma and young gun Sio is leading the charge.
Kepu is moving his career abroad at the end of the season, but he will still be eligible for Wallabies selection thanks to the 60-Test, seven-year threshold introduced this year.
They say props are like fine wine and get better with age, and Kepu will be 33 at the next World Cup while Sio will be 28, Slipper 30 and Smith 31.
"We'll miss Kepu at tight-head, it's a stretch to think Holmes will be there and there's a gap to the rest," Connolly says. "But you can argue we're not too bad in the prop stocks."
HOOKERS:
World Cup squad: Stephen Moore, Tatafu Polota-Nau, James Hanson.
2019 prospects: Tolu Latu, Nathan Charles.
Wallabies captain Stephen Moore and Polota-Nau have served with distinction for the past decade. They are 32 and 30 respectively and the time is nearing when their careers come to a close.
"I don't know if [Moore and Polota-Nau] will be around for the next World Cup, so you look at Hanson and [Saia] Faingaa who have done it before," Connolly says.
"New Zealand went through this and they got Dan Coles ready to go. The challenge is how we adapt."
Cheika loves hard-nosed Latu and he will be served best by blooding new rakes while he's got some experience to fall back on.
Hanson joined the Wallabies World Cup squad as injury cover and looms as the man to step up, while Western Force No.2 Charles will get his opportunity at some point.
SECOND ROW:
World Cup squad: Rob Simmons, Kane Douglas, Dean Mumm, Will Skelton, Sam Carter.
2019 prospects: Rory Arnold, Sam Lousi.
The Wallabies have been blessed with strong second-rowers in England after Douglas and Mumm returned to the fold thanks to the relaxed eligibility changes.
Skelton was sent home with a torn pectoral and Carter was called in as his replacement.
With the exception of Mumm, all of Australia's locks will be 30 or younger at the next World Cup. An injection of towering second-rower Arnold may add the fresh blood and all are capable of playing on.
BACK ROW:
World Cup squad: Scott Fardy, David Pocock, Michael Hooper, Ben McCalman, Sean McMahon, Wycliff Palu.
2019 prospects: Liam Gill, Ita Vaea, Brad Wilkin.
Palu's World Cup dream was shattered by a hamstring injury and his Wallabies career has ended.
The Wallabies back row was rated the strongest at the World Cup thanks to Pocock's brilliance over the ball, Hooper's defence and Fardy's determination. World player of the year nominee Pocock is just 27 years old, but has had two knee reconstructions. Both Pocock and Hooper, 24, have already played more than 50 Tests each. "The quality in the back row is there, even with Gill still around," Connolly says. "Fardy might be the stretch, but the crystal ball stuff is very difficult. One injury can change it all."
They can all suit up again in 2019 when Fardy, 31, will be the oldest.
In Fardy's favour is that he is a late bloomer, overlooked by all until the ACT Brumbies signed him as a 27-year-old. The best part is that Gill is waiting in the wings and the loss of Palu's power can be offset by another islander in Vaea.
HALFBACKS:
World Cup squad: Will Genia, Nick Phipps.
2019 prospects: Nic White, Nick Stirzaker.
Genia will leave Australian rugby after the World Cup, but can continue his Wallabies career under the eligibility changes. He will be just 31 by the time the next World Cup rolls around and can benefit from a break from the intense Super Rugby season.
"Halfback is a crucial area for us with Genia going overseas," Connolly says. "Where does the next one come from? Is it Phipps? I don't know."
Wallabies 1991 World Cup-winning captain Nick Farr-Jones rates Melbourne Rebels young gun Stirzaker a future Test No.9, while White was overlooked for the World Cup squad and now plays in France. White has hinted he may return to Australian rugby with the World Cup as a lure.
FIVE-EIGHTHS:
World Cup squad: Bernard Foley, Quade Cooper.
2019 prospects:Jack Debreczeni.
Foley has made the No.10 jersey his own and consigned Cooper to an uncertain Test future.
Cooper falls two games short of the 60-Test requirement to be able to play abroad and still be available for the Wallabies.
He has a contract with Toulon and he may have played his last game in a Wallabies jersey.
Burnout is the factor that looms large for Foley as he juggles Waratahs, Wallabies and Japan Top League duties after he signed a flexible contract to stay in Australian rugby.
INSIDE BACKS:
World Cup squad: Matt Giteau, Matt Toomua, Tevita Kuridrani.
2019 prospects: Christian Lealiifano, Kyle Godwin, Samu Kerevi.
The ARU rule change was dubbed "Giteau's Law" as the Test veteran revived his international career.
His presence added crucial experience to the Wallabies' back line, but it also kept Toomua out of the starting XV for all but one game.
It's unlikely Giteau will look beyond the World Cup, while Lealiifano can consider himself the most unlucky player not to be picked this year.
"This year has shown that experience is very important in a World Cup," Connolly says. "You can't just worry about the World Cup in four years, you have to develop all the time. Every Test is very important."
The ARU should do all it can to keep Lealiifano because he looms as a linchpin if Giteau calls time.
WINGERS:
World Cup squad: Adam Ashley-Cooper, Drew Mitchell, Henry Speight, Joseph Tomane, Rob Horne.
2019 prospects: Taqele Naiyaravoro, Sefanaia Naivalu.
Test centurion Ashley-Cooper is yet to decide on his international future, but he will leave Australia after the World Cup and move to France.
Whether he and Mitchell want to play on will change the shape of the Wallabies' back line.
But waiting in the wings is powerhouse Naiyaravoro and Naivalu. Giant former Waratah Naiyaravoro is playing in Scotland, but expect him to return to Australia in the coming years as Cheika builds for the future.
Tomane and Speight got limited chances at the World Cup, but they are options in 2019. Horne is Mr Consistent and has shown why he is one of our most reliable and courageous players.
FULLBACKS:
World Cup squad: Israel Folau, Kurtley Beale.
2019 prospects: Andrew Kellaway, Karmichael Hunt.
Folau wasn't at his peak during the World Cup but, if he stays in rugby for another four years, he will be a weapon at the next tournament. His challenge is burnout as he plays almost 12 months every year, switching between the Waratahs, the Wallabies and Japan.
Kellaway is a star on the rise. Hunt didn't really fire a shot in his first season of Super Rugby but, if he can hang around for four years and learn more about the game, he will be an asset as a winger or fullback.
"We've got to get our head around this 60-Test rule," Connolly says. "There's no way a player can go for 12 months of the year. The onus is on the coaching to develop more players. We're lucky we've got five provinces [in Super Rugby].
"The world has changed, there's a logjam waiting so you can't relax because the rest of the world has caught up."