So the Earth has been around for billions of years and hominids for millions of years but the aliens just happen to be showing up right now? Seems improbable.
Maybe they have been coming here for hundreds of thousands of years or more.
Maybe they are the reason for the “missing link”.
Meaning they bred the ape that crawled out of the jungle of Africa 250,000 years ago and bred it to create homo sapiens. Maybe WE are related to one of the alien species.
There's quite a bit of information that would suggest they, or something, may have been here before.