The Hendrick Motorsport Chevrolet driver missed out on the playoffs for the first time since joining the Cup Series in 2016 after failing to secure the win he needed to progress.
Bubba Wallace therefore secured the 16th and final spot on points, leaving 2020 champion Elliott unable to end this year higher than 17th.
Elliott holds the fifth-best average finish among full-time drivers this year, but his season was compromised by missing six races due to a leg injury sustained in a snowboarding accident. He then missed a seventh after being suspended for intentionally wrecking Denny Hamlin at Charlotte, which put him into a must-win situation as he was unlikely to make the cut on points.
A fourth-place finish at Daytona was a good day on its own, but not what he needed.
Elliott explained he was unable to "stay locked onto Kevin [Harvick] like I needed to to surge the bottom lane forward" in the closing phases as RFK Racing team-mates Chris Buescher and Brad Keselowski controlled the top lane to secure a 1-2 finish.
Elliott may be out of the driver's playoffs, but his car remains in the fight for the championship on owner's points.
"That's a big deal, probably much bigger than a lot of people realise to our team," he said.
"Looking forward to these next 10. Try to make a little noise on that side of things and just try to get ready and prepared for next year.
"But I appreciate everybody's support through this season. Hasn't been what I would want by any means.
"Certainly going to be some lessons taken from it, and I think we'll be better for it on the other end."
Reflecting on reaching the playoffs for the first time in his career, having joined the Cup Series full-time in 2018, 23XI Racing Toyota driver Wallace admitted to feeling "stressed" during the race.
He entered Saturday's race at Daytona with the 16th and final playoff spot within his hands, but Elliott and 15 others could knock Wallace out of the running with a victory.
But a repeat winner in Buescher meant 12th was enough for Wallace, who joins team-mate Tyler Reddick in the round of 16.
"That was the most stressed but also the most locked in I've ever been," he said.
"Knowing that this place is mostly out of your control, I just tried to focus on doing the things that I could do."
He added: "I’m just relieved. I apologised to my wife (Amanda) all week. I haven’t been myself – I’ve been stressing.
"Thankful that we are in it. That is the most calm I’ve ever been. It’s ass-backwards.
"You come to Daytona, and you focus so much on controlling the things that you can control. My stubborn ass never wants to listen to people telling me that. I finally did that, and we are locked in."
Among those who congratulated him after the race was 23XI Racing team co-owner and NBA legend Michael Jordan.
Wallace will enter the playoffs in 16th place after the reset with zero bonus points. Positions 13th through 16th will be eliminated after the third race of the playoffs, which includes Kansas Speedway where Wallace is the defending winner.
