'The definition of insanity': Eddie Jones gets 'factual' on World Cup selections

Eddie Jones has finally revealed the reason for omitting Quade Cooper from Australia's Rugby World Cup squad.

Cooper's axing and the overlooking of fellow elder statesman and former Test captain Michael Hooper were the most contentious of several eyebrow-raising squad decisions from Jones.

Cooper was axed in favour of greenhorn playmakers Carter Gordon and Ben Donaldson in a selection gamble that spectacularly backfired as the Wallabies failed to progress out of the knockout stages for the first time in World Cup history.

Even more perplexing to disillusioned fans and former greats was how Cooper's dumping came after the 35-year-old was captured on TV as the most vocal figure in the Wallabies' huddle immediately after almost beating the All Blacks in Dunedin in August.

But Jones on Tuesday said the Wallabies' inability once again to close out a big game - this time when Cooper was the five-eighth "finisher" after coming on as a replacement - was the final straw.

Instead of being heartened by Australia almost snapping a 22-year, 28-Test winless drought in New Zealand in their final match before leaving for France, the coach made a shock decision to shift to his youth policy after the 23-20 heartbreaker.

"Well, we weren't good enough to beat the All Blacks. We had them on toast 17-3 and we couldn't finish the game off," Jones said.

"Let's be quite factual about that. I just thought we're not going to get anywhere with that group of players.

"I probably thought they'd maximised themselves out and we'd had that group of players for a period of time.

"And I always go back to the definition of insanity: you know, keep doing the same thing, expect different results.

"So I tried something different, went for youth, and it will have favourable results further down the track."

Facing the media for the first time since Australia's failure to make the quarter-finals in France, Jones is backing the same core group of young stars to take the Wallabies to the 2027 World Cup on home soil.

"If you look at the number of players we took to the World Cup who are still to reach their peak - players like (Fraser) McReight, (Tate) McDermott, (Ben) Donaldson, (Tom) Hooper, (Max) Jorgensen - there are a number of players there who are at the start of their international career," he said.

"Most of them showed during the World Cup that they have enough to really go forward and be very good players for Australia.

"We throw in a few other players from around the place and we have a nucleus of a really good team."

Saying he didn't return home "to eat fish and chips and drink flat white at Coogee Beach", the 63-year-old maintains he must serve as an agent for change for Australian rugby to move forward after the Wallabies slumped to a new low of No.10 in the world.

"Everyone hates change because it is uncomfortable," Jones said.

"Everyone likes the status quo.

"And we had the courage, whether it be the right courage, to make the choice that we would go with a younger squad. The young squad will stand Australia in good stead.

"You've just got to look at the quarter-finals and look where we're at.

"We're not at that level and we need to get to that level, and that can be done through hard work.

"It can be done through smart planning, through consistently thinking about world-class standards, and that's what we need to get to in Australian rugby.''