
And of course the problem is when they eventually leave F1 because they don't need anymore. 3 this year, maybe 4 with Renault. Indeed I've read news about another team, Merce

Conclusion: first, it's a very bad point for Heidfeld that I was thinking being the perfect second driver for Mercedes. But what about Renault? They apparently admit that the Polish negotiates with Mercedes, but they don't want to comment about it... If you add that this week, Carlos Ghosn, the Renault Director, said he was pessimistic about the future of its team and the overall future of F1.
And what about this news of new car manufacturer interested by joining F1: Volkswagen? Well, at least, they have a good point of view about this project: they are only interesting in providing engines. But they don't think about entering this jungle now because with current rules, building an engine is not that good for image as there are so many restrictions that all engines are too close together. This is one of the main working point of the F1 in the future and there is a good opportunity to find new developments track: make the engines cleaner!