Also, cell phones have a dial tone, and in most instances, people do NOT have to say Hello, or Goodbye on the phone.
I’ve never heard a dial tone after the other person hung up, regardless of the kind of phone I’m using. Is this just an invention of the media?
No, there is no dial tone when the other person hangs up. As you suspected, this is just Hollywood taking artistic license. In real life when you take the handset off-hook, you get connected to the CO (Central Office) and it gives you a dial tone (actually it’s two tones mixed together) to let you know you have an open line and can start dialing. Once you start dialing the dial tone disappears. In a movie or TV show, they need some audible indication to let the audience know the other person has hung up so they came up with using the dial tone.
They use the same principle in action movies. When the bad guy is about to shoot the unarmed good guy he has just captured, he cocks the trigger while bidding him farewell. You would think the gun should still fire even if he didn’t do this. After all, he doesn’t have to cock it each time if he fires more than one shot. It’s just done the first time for dramatic effect.