Red Bull founder Dietrich Mateschitz "absolutely" has the right to leave Formula 1 if unhappy with the direction of the 2021 regulations.
The upcoming six months are expected to be critical as negotiations continue to form a new Concorde Agreement to come into effect in two years time.
Liberty Media is desperate to introduce measures both sporting and commercial to level the playing field but that has been met by resistance from manufacturers.
Red Bull have raised questions about the policing of a proposed budget cap but it is the overall appeal of F1 which team boss Christian Horner believes will sway Mateschitz's commitment.
Asked by Motorsport.com if pulling the plug on both teams was possible, the Briton replied: "Absolutely, and that's his right.
"He's passionate about motorsport, he's passionate about F1, he's enthusiastic about the new engine partnership with Honda and the potential that brings, but of course F1 has to deliver for the Red Bull brand as well.
"It needs to be exciting, it needs to be cost-effective, the racing's got to be great, and we need to be able to play on an equal and level playing field with OEM and manufacturer teams.
"I think like all of us he's waiting to see what is F1 post-2020."
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This week, the FIA has released more tenders for standardised parts, while Ross Brawn claims work on the 2021 car design has seen a 40% improvement in downforce kept when following another car.
Regardless of how well the new rules shape up, however, former F1 supremo Bernie Ecclestone claims the longer talks go on regarding the new Concorde Agreement, the higher the chance of a big name leaving.
"Maybe Mercedes will be stuck into Formula E because they think Formula E is more in line with the way the car industry is going to go," he suggested to Motorsport.com.
"Red Bull don't need to be in it because they get so much publicity from all the other things they do. For them, if they stopped it's not going to damage them at all.
"People think Ferrari would never stop, but the Ferrari brand is so strong it would be difficult to damage Ferrari. They could easily do something else in motorsport.
"The longer they leave it, the worse it is for everyone – it's worse for the teams, worse for Liberty."
