At any time they wish, the conquest of Earth would be a simple task. They would have weapons and capabilities we cannot even imagine. They could use advance nano technology to control our minds and enslave us, if they wanted an army of obedient Earthling workers to strip our small planet of resources.
Hmmm, maybe the visitors are responsible for climate change. LOL
Ever hear of that theory from, I think it was Sitchin, who figured we could be genetically engineered, and part of that engineering was our inordinate love of gold. We’d accumulate it over thousands of years, and they come back, spray for humans, and collect the neatly stacked metals from our vaults...