With Fernando Alonso switching over to Ferrari and Sauber BMW pulling out of Formula 1, signing a contract with Renault is the ideal thing to for Robert Kubica, which of course he did. The Polish driver will replace Fernando Alonso for season 2010 at Renault.
“I am very happy I will be joining Renault in the [...]

Not getting desirable results
Economic crisis
Getting bored of it

“It has been clear for some time that motorsport cannot ignore the world economic crisis,” the FIA said in a statement. “Car manufacturers cannot be expected to continue to pour large sums of money into Formula One when their survival depends on redundancies, plant closures and the support [...]

With 1 victory under their belt over 3 years, the Hinwil based team (BMW Sauber) has just confirm their exit on Formula 1. They will leave at the end of the season. BMW Motorsport Director Mario Theissen says:
“Of course, we, the employees in Hinwil and Munich, would all have liked to continue this ambitious campaign [...]