Koe's Calgary rink came into the 10th end down by three, but couldn't muster the comeback, scoring just a single point in the final end against the Swiss team.
Switzerland stole single points in the first two ends, and padded their lead with deuces in the sixth and ninth ends en route to the victory.
"We definitely didn't want to lose that game," said lead Nolan Thiessen. "But after yesterday, it was tough to get fired up. But no excuses. They played better than us."
Canada had two chances on Saturday to reach Sunday's gold-medal game, but fell short to Norway's Thomas Ulsrud in the 1-2 Page playoff game, and then to Sweden's Oskar Eriksson in the semifinal. Ulsrud led from start to finish in defeating Sweden 8-3 to claim the gold medal later Sunday.
"I thought we played well in the one-two game and the semi," sad Koe. "We were very close. But in games like that where the other teams are playing well, you have to make the last shot of the end sometimes and we let our chances slip away."
Despite failing to medal at the world championships, Canadian coach Rick Lang says there's no reason to push any panic buttons, considering Canada has finished in the top six at every international curling event this season.
"Twenty-four hours ago, we were within a shot or two of being in the final here," said Lang. "And then we have a bad 24 hours and that chat starts. But we had a great team here. They didn't play like themselves the last couple days, but they were worthy Brier champions.
"We sent a great team here. They just didn't have a good day, and that can happen to anybody. The level of competition here is strong and getting stronger. We just have to answer the bell, that's all."
Koe said he was proud of the way the team performed in Beijing.
"That's the way we've always done things," he said. "Some people might not like our style or our game, but we fight. It's not always the prettiest, but we get things done.
"I'm proud of the guys. We had a great run. World championship, two Brier titles, a Brier final — obviously this was very disappointing, but it's been a great team."