Fire them all. Leno is partially innocent in this. His contract requires him to work for NBC and maybe his contract included wording that he'd be given back the 11:30 time if the 10 failed. Get rid of him anyway he's been around too long.
Fire the ugly O'Brien for behaving like a complete asshole since thiis happened. whether he likes how it has happened or not is of little importance. He failed to bring ratings and NBC is his employer. The way his mouth has been running in other jobs he would have been fired.
Fire that disgraceful Kimmel thing. He only had a shot at success because of Ben Stein when he was the sidekick on Ben Stein's Money show. After Kimme;s behavior last night he also deserves to be shown the door.
Bring in new talent. Better yet bring in talent.