Red Bull could target Le Mans 24 Hours success with an Aston Martin Valkyrie-based hypercar instead of Formula 1, if it does not see a viable post-2020 grand prix future.
The energy drinks company took over Jaguar's works entry for the 2005 F1 season and blossomed into the dominant force from 2010-13, winning four consecutive drivers' and constructors' titles.
Red Bull has been reduced to a sporadic race winner in the V6 turbo-hybrid era that began in 2014.
It will switch from being a Renault engine customer to having de facto works Honda status for 2019 in a bid to fight for titles again.
F1 owner Liberty Media is targeting a commercial and regulatory revolution once the current Concorde Agreement expires after the 2020 season, but has failed to make significant progress.
Red Bull motorsport advisor Dr Helmut Marko says his team is not interested in becoming a customer again and has made it clear that Red Bull will not be held to ransom over planned rule changes.
"We have an agreement until 2020," Marko told Autosport.
"As long as there is no engine regulation and no Concorde Agreement, neither Red Bull nor Honda will make a decision.
"However, we will certainly not become dependent again, as we have been in the past, when we were begging others and statements and promises were not kept."
Red Bull's current Honda deal includes the 2019 and 2020 seasons. Beyond then, Red Bull's choices appear limited if there are not favourable terms to continue.
"Stop is the option," said Marko.
"Or do something else, other racing series.
"With the Valkyrie, Le Mans could be an option with hypercar rules. We went through with it, and it's a sensational success.
"The cars were all sold out immediately. That's another good pillar for Red Bull Technologies."
Red Bull helped Aston Martin developed the Valkyrie, a limited-run road hypercar, with its F1 technical director Adrian Newey a key part of the project. A track version of the car has already been produced.
The WEC is working on new regulations to replace LMP1 as the top division, with the inaugural season for hypercar-based entries taking place across 2020 and 2021.
One of the fundamental parts of F1 owner Liberty Media's vision for 2021 onwards is reduced costs, and Marko suggested Red Bull's interest World Endurance Championship's flagship race does not depend entirely on a complete withdrawal from F1.
"If there was a cost cap in Formula 1, we would have to cut people," he said.
"We don't necessarily want that.
"We could then use them in such projects [as Le Mans].
"It still looks like you can run in the WEC at a reasonable cost with the base of our Valkyrie.
"Although Red Bull has never been to the 24 Hours, that's something we're thinking about.
"The main financial burden would be on Aston Martin, which is also clear, because at Le Mans the manufacturer wins. "But that would fit into our concept."