I found a loophole regarding Andrea Romano's statement that "the whole generation has died". Well, the statement refers to Aang right? Well, technically Aang isn't from Zuko's, Katara's, etc generation, he's from a generation 100 years ago and the only surviving members are Bumi and Aang, and Aang has been confirmed to be dead while Bumi probably wouldn't live to Korra's time. Aang's generation did die out. So.....I found a loophole :P.