For a number of years, I've entertained the whole discussion of UFOs and aliens....to the point that I have no doubt of the existence. But I've come to the key question....if you've come from far, far, far away....you've arrived to discover that Earth is probably a thousand years to a million years behind your 'standard'....why linger?
If you had your typical PhD American scientist, on some junket 'tour' to a planet where some beings existed but they were at the mid-1700s 'pace-of-things'.....would you go and linger long? In a group of ten, I would imagine there would be a vote, and some minor agreement to stick around for 90 days but mostly admit that there's just not much to 'discover'. One or two of the PhD guys would be all pepped-up to spend years there to understand the vast nature of this society. The rest? No....simply move on.
My gut feeling is that some of these alien cultures have reached a level of boredom....being more than 20,000 years more advanced, and they would have voted for permanently visiting Earth....simply out of boredom.
Yorg and Yurg would get up daily....shower...soak up 1,500 calories of some bean dip mixture....then spend a dozen hours watching Italian operas, Mexican soap operas, and reruns of Dallas. Later, they'd have a alien staff meeting where each shared their discovery of the day, then soak up some more bean dip, and sleep while listening to some Elvis tunes.
I think the bosses of Yorg and Yurg would occasionally visit....asking why continuing the mission but find that everyone is addicted to the Earth reality show.
It's reached some level where a dozen-odd alien groups are basically hiding out....viewing the whole landscape of Earth reality, and they simply can't get enough.
But adding to this mess....the Pentagon has figured all of this out, and basically can't believe the soap opera story. They want the evil-threat story to be key part to telling this.
Where this goes, if you were finding out the whole situation, and that you were mostly the entertainment for these awful bored aliens? That's the key question.....how you would handle this.