It's "their" planet. They deserve it because of their wealth. It's how greed works. Most people aren't overridden with greed and so don't understand the concept fully. It's a sickness... an addiction. So all they need are enough slaves to keep them fed and keep all their toys running (a couple million? Five?) and repair their vintage cars. You know, rich people shit. They'll interbreed and voila! The species will devolve back into tree frogs or whatever we came from -

and that will be that.

No way to stop it now, that time has LONG past. So, have fun. But hurry!