"Three hundred years ago, Earth was discovered by three civilizations, or what you might call three different species of aliens. They found Earth in a staggered sequence but all roughly around three hundred years ago. They all found out that Earth was a planet teeming with life, even giving birth to an elementary civilization."
"For a planet with an elementary civilization, those three civilizations showed little interest. More interests and overarching rule are often the subjects in your Earth's science fiction movies. Reality is that, for any far-off civilization, it's improbable for them to expend significant effort on ruling a life group that is biologically different from them on such a planet. It's both troublesome and unnecessary, as they are too far away."