Red Bull team principal Christian Horner says teams have little chance of closing the "enormous gap" to Mercedes next season.
Mercedes has dominated the past two seasons since the introduction of the 1.6-litre V6 turbo power units, with the team only failing to win three races in each year. While Ferrari made clear improvements in 2015 to become the nearest challenge, Mercedes still managed to exceed its points total this season compared to last.
Horner expects the gap to prove too big to close over the winter even if Mercedes is unlikely to be able to find as much lap time as its rivals.
"The regulations are extremely stable for next year, so obviously Mercedes will inevitably carry on the dominance," Horner said. "Such is their margin. But they will find gains over the winter.
"They will undoubtedly be near the top of the curve and get lesser returns than others. But it is an enormous gap for any of the teams to fill. I am not sure what the bookies would offer for a repeat performance next year. The odds are not good."
"I honestly think they increased the gap this year, and obviously Ferrari caught up a little bit," Ricciardo said. "But when Mercedes really wanted to turn it on, they could. They'll still be the team to beat next year and they will be hard to beat, but hopefully it doesn't go on too much longer."
Use the red tabs on either side of the screen to scroll through more Formula One news and features