Amid all the talk of Formula 1 rules changes for 2021 it's easy to overlook one very important fact. As there is no new Concorde Agreement, or whatever its future replacement might be called, none of the teams are formally committed to the championship beyond the end of next season - and so there's no guarantee that there will still be 20 cars on the grid.
Whether the decision to ultimately sign up for 2021 is made by an unsentimental board of directors with an eye on the bottom line or a mega wealthy individual who is involved largely because of personal enthusiasm, any call on remaining in F1 has to make financial sense.
A decade ago Honda, Toyota and BMW all pulled the plug when the economic tide turned, while the likes of Tony Fernandes and Vijay Mallya, who pumped millions into F1 essentially because they were fans, are no longer around.
One man who has to make a call in the coming months on his future participation in F1 is Gene Haas - and Liberty Media has to be careful, because there's no guarantee that he will decide to extend his involvement beyond next season.