Michelin appears uninterested in returning to F1 even after 2020.
The French marque makes tyres for Le Mans, Formula E and MotoGP, but motor racing boss Pascal Couasnon says the rules are not right for a return to F1.
"It is not an option as long as there is no change in the regulations," he told AS newspaper.
"For us, it does not make sense to manufacture 13 inch tyres when these are not seen on street cars. It would be different with 18 inch wheels, but it seems to me that the 2021 changes are focused on the engine and the budget," Couasnon added.
"The most important thing for us is the technological challenge — to have something to learn from. Otherwise we will not invest," he said.