They didn't quit. Maybe they don't know how.
"It's an extremely hard-working group, and they understand it's a long game," first-year coach Chip Kelly said. "You can't get discouraged when you're not successful early."
Sure you can. They just don't.
Credit Kelly, a nutty football professor who insists that football should be fun. Credit sports science; all that good eating and hard sleeping and endless massage therapy seems to making the Eagles stronger as other teams weaken in December. Credit the good-apple leaders absent or muted last season: new pass rusher Connor Barwin; Kelce, lost last season to injury; Nick Foles, maturing into a team leader in his second year.
Credit who or what you will.
At 8-5 after the Snow Bowl, this group of Eagles has won five straight and has survived every sort of test in this unlikely, remarkable season.
"I don't think this group gives up," Kelly said. "I think they've got way too much invested, and I think when you have invested in something, it's a lot more difficult to quit."
Indeed, when Kelly succeeded Andy Reid and announced he would bring his Machine Gun offense from Oregon to the NFL, and, with it, a 3-4 defensive scheme, veteran pillars bought in.
Defensive end Trent Cole and left tackle Jason Peters, both Pro Bowl talents in their 30s, lost weight and learned the schemes. Cole's defense smothered the Lions, who gained 228 yards from scrimmage and fumbled the ball away three times. Peters' offense wore down the Lions . . . as he expected.
"Even when they went up 14 to nothing there was no doubt we were going to win it," Peters said.
He anchored an offensive line that gutted Detroit's greatest strength in a game scripted to play to that strength.
Old Man Winter was supposed to spit an inch of flurries. Instead, that cold-hearted demon spewed 7 inches more. In theory, that should have dealt a huge advantage to the Lions and their huge defensive tackles, Ndamukong Suh and Nick Fairley.
Instead, playing in shin-deep snow the consistency of beach sand, the Eagles simplified their plan and ran at, and over, Fairley and Suh.
"We physically outplayed them," Kelce said.
"At the end, I felt like they were out of it," Peters said. "They were trying, but they just couldn't stop us."
Therein lay the Eagles' salvation.
Foles, the newest toast of the town, had played abysmally, the way a Texas quarterback with Arizona schooling would be expected to play in 27-degree weather.
"When I was making throws, I couldn't really zip them," said Foles, who, as usual, managed to minimize his mistakes - an attribute of all winning quarterbacks.
"It was a big win, because it does allow us to grow together, as a team," Foles said. "Nobody wavered from what we knew we would accomplish."
Foles had great faith, if not great numbers: He was 11-for-22 for 179 yards, but it was an uglier than that; as ugly as the day.
Snow fell sideways. Wind sliced into the stadium from the north, leaving patrons marooned in their cars in traffic snarls along the region's highways.
In the fresh snow the Lions' lines ruled the day. Foles threw his first interception of the season, which set up the Lions' second-quarter touchdown, and they led, 8-0, at the half.
The Eagles then gave up a touchdown on a punt return for a score with 6:37 to play in the third quarter. It was cold and miserable and snow was as deep as 10 inches where the periodic shoveling left mini-drifts along the yard lines. The first loss since Halloween seemed inevitable.
Maybe that edition of this team would have folded. Maybe this edition has grown.
"We don't let those types of excuses creep up in our minds," Barwin said.
Foles righted himself on the next drive with three big strikes, the last a touchdown to DeSean Jackson. Early in the fourth, the Birds benefited from a poor roughing call on Fairley, setting up LeSean McCoy's 40-yard run, en route to an Eagles record 217 rushing yards, but the Lions promptly counterpunched with a 98-yard kickoff return for a 20-14 lead.
"You tell me we're going to give up two touchdowns on special teams," said special-teams ace Casey Matthews, "and you'll have a hard time convincing me we're going to win."
But win, they did.
In the next series, McCoy sprinted 57 yards on the Eagles' third play, and Riley Cooper caught a two-point conversion pass, his second strong catch of the game, to make it 22-20.
These Lions could have starred in the Wizard of Oz, so heartless, so dumb and so cowardly did they play. They botched a screen pass, punted, then saw McCoy, Foles and Bryce Brown run for a total of 63 yards on consecutive plays.
Matthew Stafford then fumbled for the fifth time, and, for the first time, lost it, and that was that. The Lions were the punchline in this cruel winter joke played on the nation's meteorologists.
"So fun," Barwin said. "It was like those games you used to see on NFL Films."
A perfect comparison for the Eagles, who played like players of that mettle; tough men who embraced the elements and endured their failures and won a snow-globe classic.