Major changes at all the broadcast networks

Numbers are down for fall TV, though broadcast television still remains the best way for advertisers to reach the masses. The new TV season kicks off just as there's leadership change at all four broadcast networks. Les Moonves is out at CBS following allegations of sexual assault. At NBC, Bob Greenblatt decided it was time to go, leaving while the network he successfully ran for several years was at a high point. And the merging of Disney and Fox is also leading to job changes at the top of ABC.