Why in American movies and television series when ending a phone conversation they do not say bye?

Why most of the times in American movies and television series when ending a phone conversation they do not say bye or any “farewell expression”, while people in real life do use such expression by phone?Why in American movies and television series when ending a phone conversation they do not say bye?it's too anti-climactic. waste of time. same reason you never see them go to the bathroomWhy in American movies and television series when ending a phone conversation they do not say bye?some people just dont say it...i personaly dont because i hate talking on the telly anyway...Why in American movies and television series when ending a phone conversation they do not say bye?Because the Americans are rude buggers and want to come off as a sort of hard man