It is also doubtful whether lock Bakkies Botha, who was sent home earlier this week with an Achilles' injury, will play internationally again. All three forwards were instrumental players in the 2007 World Cup-winning side.
"It was a brilliant journey, something that none of you guys can take away from me. There's a time to come and a time to go. So I think the journey for me is over," De Villiers said.
"I wanted to be the best me that I could be, the way that I am is the way that I want to be remembered."
Smit, whose general play has been usurped by Bismarck du Plessis, said he was also disappointed to be leaving his final World Cup earlier than hoped.
"It's a sad occasion, you never prepare for how it ends because you want it to be a fairytale, you want it to be a final, but it hasn't worked out that way," the 33-year-old Smit, who had won 111 caps, said.
"It would be silly to take that seven years (as captain) and judge it by what happened today.
"I have been blessed to be in charge of these guys and run out with them and blessed to be captain of the Springboks.
"I think it's not important how I want to be remembered. People always talk about a legacy but for me it has been a privilege to be able to play with the guys that have made my career what it was.
"I am devastated today. It's the end of a chapter and I am proud of the guys, I have played with and really proud to have been a Springbok."
The match had been billed as a clash between an aging South Africa side with a conservative style of play against a young Wallabies team with potentially the world's best backline, and in the end, the Springboks' style proved their downfall.
While their kicking game created pressure which allowed them to win penalties, or poach turnovers from errors and keep the scoreboard ticking over, four years of failing to develop a true attacking thrust in their backline was evident.
Time and again the ball was handed to hard-charging forwards in the midfield to break the advantage line, which they rarely did, while their backs became too lateral.
They managed just one line break when Jean de Villiers breached the Wallabies' stretched defence but his pass to fullback Pat Lambie was ruled forward by referee Bryce Lawrence after he had crossed the line early in the second half.
That try and, no doubt, conversion by the metronomic Morne Steyn would have given the Springboks a 10-8 lead and it is doubtful whether Australia would have been able to re-group with 30 minutes remaining and the South Africans' confidence growing.
"At halftime we felt we had the upper hand even though we were a couple of points behind. In the second half, we had one or two calls go against us," centre De Villiers said.
"We have only got ourselves to blame. Sometimes you get one or two opportunities and you need to take them, and Australia did that."