Ricciardo leaves the team after two disappointing seasons at McLaren, with the team deciding in the summer to end his contract one year early and move for rookie Oscar Piastri, who got his first run with the team in Tuesday's post-season test at Yas Marina.
The Australian's struggles proved particularly costly in the constructors' championship, as McLaren fell from fourth to fifth after finishing 14 points behind Alpine.
Ricciardo gathered only 37 points compared to teammate Lando Norris' 122, so even just scoring half of Norris' points total would have easily yielded fourth.
But team principal Seidl has always maintained that the failure to make Ricciardo tick was a joint responsibility between the driver and the Woking team and refuses to blame Ricciardo's situation for losing the position.
"I'm far away from just blaming the situation with Daniel for not scoring P4 this year," Seidl said after Sunday's season finale.
"In the end I'm aware as well about my responsibility, the team's responsibility not to get it to work together with Daniel in the way we were hoping for, despite the great commitment that was taken on Daniel's side and on ours.
"That's part of not scoring the points as a team that you wanted or could have scored. It's part of the sport and that's something that we try to address or improve for next year."
Regardless of Ricciardo's situation, McLaren was generally outperformed by Alpine, whose frequent reliability issues kept McLaren in the race longer than it perhaps had any right to be.
Seidl acknowledged that P5 was a "fair reflection of where we have been throughout the season" and that Alpine deserved to finish ahead because it "did a better job".
Still, the disappointing Ricciardo-McLaren chapter ended on a high as the 33-year-old moved up from 13th to ninth in the Abu Dhabi Grand Prix, and Seidl was pleased to finish the chapter in the best possible way.
"The entire weekend, including the farewell celebration that we had in the factory, the farewell celebration at the team barbecue on Thursday night, the three days here knowing that whatever we did was the last time together with Daniel, it was emotional," Seidl added.
"At the same time, we made sure throughout the weekend that we kept the focus on still trying to pull off the best possible result because we wanted to keep the pressure up on Alpine.
"The last time I wished Daniel a good race on the grid was emotional, but I think it was great to see that he was pulling off a good race for us. Getting back into the points from P13 was down to a great drive together with great work from his side of the garage and the pit wall.
"I think we finished our time together on the best possible high, which was the aim after all the announcements of the summer break."
