Horner acknowledged that Red Bull boss Dietrich Mateschitz could pull the plug if he's not happy with the shape of F1 in 2021.
"I think like all of us he's waiting to see what is F1 post-2020".
However, the Briton was keen to make clear that a slow start with the team's new engine partner, would not be key to Mateschitz's decision. "Through good days and bad days he's always been tremendously supportive, and invested probably more into F1 than any other entity".
"We've achieved more than 50 Grand Prix victories and eight World Championships working as one team".
Ecclestone believes that while there is no Concorde, there remains a risk that teams or manufacturers could pull out of the sport.
Indeed, Ecclestone admits that the delay in agreeing a new Concorde is making it harder for the teams.
"I still think we are about two tenths per lap behind Ferrari, and just ahead of Mercedes", he added. They get so much publicity from all the other things they do. People think Ferrari would never stop, but the Ferrari brand is so, so strong it would be hard to damage Ferrari.
"The longer they leave it, the worse it is for everyone", he warns, "it's worse for the teams, worse for Liberty".
"I think the most important thing is to work as a team", said Horner during a press conference in Japan".
Much of this is out of Ricciardo's hands, because we already know he can win races in the right team.
"I think if I was a shareholder I'd be happier once all that got put to bed", he admits.