Hadden declared in the aftermath of Sunday night's scrappy 19-13 defeat that he expects his squad to mature within three seasons.
But after analysing the near-miss at the Stade de France, it really hit home that a glorious opportunity to reach the semi-finals had been squandered.
Hadden now believes Scotland have nothing to fear in the Six Nations and has reassessed his initial target of emerging as contenders by 2010.
"We're gunning for the Six Nations," said the 53-year-old, who revealed he will now be taking some time off after a hectic year.
"There is no doubt in my mind that this team is capable of continuing to make the progress they have made so far.
"Under these circumstances, we have to fancy our chances in the Six Nations. There's nothing for us to be frightened of there.
"You've seen there have been so many tight games in this World Cup, and the matches will continue to be tight when the Six Nations starts."
Hadden's big hope is that he will be preparing for Scotland's next big assignment with the majority of his squad still in rude health.
"To enter the tournament knowing you have a real chance is something we're quite proud of," he said.
"But there are two big problems. What will the situation be in terms of injuries come the Six Nations given the intensity of the World Cup?
"And how are the players going to cope when they go back to their clubs?
"With 18 of our 30 not playing in Scotland anymore, they will not be available for the weekend before our first international.
"That has always been a massive advantage to us."
Hadden's defiant tone at the failure to progress to the semi-finals had turned to anger as he realised just how close Scotland had come.
"We're bitterly disappointed and absolutely gutted to be out of the World Cup at this stage. We had a real opportunity," he said.
"Obviously it was never going to be easy, and the Argentinians were going to pile pressure on us.
"But I've watched the game again, and the number or elementary errors we made in the first half was extremely disappointing."