well assuming "Good Earth" would be a better version of our planet this is my answer.
A good earth is where everyone is just good people always helping out and caring for one another. A good earth would be clean and fresh with out all the Deforestation that we have today. Cites would have no smog and kids would go outside to play rather that sitting on their phones all day. All in all, a good earth would be perfect and have no flaws which is why it does not exist