Why did Jay Leno quit the tonight show?

Jay Leno's Contract with NBC expires in Dec 2009. NBC would have to renew their contract for 2010 and so on. NBC did not like being placed on a compromising situation like they had when David Letterman left to CBS. So to minimize damage control, and not give Jay the power for a ridiculous demands (A new chin?) they decided to remove Jay's star power by pre-emptively putting him on the bench and giving The Tonight Show to Conan O'Brien. Jay's last day on the Tonight Show is May 29,2009