Despite frequently talking about his squad's depth, Gustavsson rarely turned to his bench during Australia's campaign and on Saturday named an unchanged starting line-up, despite a three-day turnaround, from the 3-1 semi-final loss to England.
The gamble of not calling on fresh legs backfired as the lethargic Matildas' best-ever World Cup ended on a sour note.
For most of the game, Australia were dominated by the energetic Swedes.
Fridolina Rolfo gave Sweden the lead on the half-hour mark from the penalty spot and Kosovare Asllani added a long-range second in the 62nd minute.
Australia's largely blunted, and seemingly exhausted, attack were unable to mount a comeback.
Gustavsson said his often-repeated mantra that it would take "23 in 23" didn't "necessarily mean that every player should play" but that they all had a role.
"If I would have rotated a lot of players and then lose it would be 'why didn't you stick with it?'. And if I (was) not rotating and lose, that will be a sharp question, which is fair," Gustavsson said.
Of the 23-player squad, only 14 featured in an average of 30 or more minutes per match while Caitlin Foord, Katrina Gorry, Kyra Cooney-Cross, Ellie Carpenter and Steph Catley were run into the ground.
"We've had a clear strategy going into tournaments based on experience but also based on some stats," Gustavsson said.
"If you look at both men's and women's big tournaments and you look at teams that have gone far and won a lot of medals, continuity in starting lineup and less rotation in rosters have been a success factor.
"And with the relationship, the more time you spend together, the better you play together. It's not necessarily always about the best players.
"But I also want to say this with the biggest respect to my game changers (substitutes), I'm not criticising them by saying this, the players know that this has been a clear strategy. You saw it in the Olympics, you saw it now.
"It might be the reason why this team have been able to break barriers and bypass and break records and create history, that could be the reason why."
At 1-0 down, Gustavsson turned to Emily van Egmond and Cortnee Vine off the bench on the hour mark but Sweden scored two minutes later.
"I'm not blaming the two subs on that. It's just the momentum and the timing of it and that hurt us a bit tonight," he said.
"I still stand by my decision (to limit rotation) and believe in what's best for the team."
Captain Sam Kerr went down screaming in pain holding her right calf - the opposite leg to her previous injury - after a challenge from Magdalena Eriksson in the 75th minute.
Kerr returned to the fray and played down the scare as a knock to the "belly" of her calf, which paled in comparison to her disappointment.
"We're really disappointed," Kerr said.
"Fourth again. It feels like the worst position to come.
"But as a whole, the whole tournament, we have to be really proud."
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