I Agree But
I have a hard time believing that Earth would not have been already settled by aliens under those circumstances. A prime directive deterrent makes little sense given that it would not have applied during most of Earth's history and the chances that they just arrived are slim during our brief existence on this planet are slim. Something like 1 in 250 (H erectus or clear tool use / period of land life) at best to 50 to 100 /4 billion at worst. It is also hard to believe that even if living in space is generally preferred due to an extended period of space faring prior to arriving here that no small fraction would desire to explore living on a planet.