That’s a theory.
Here is another one....our planet has ALREADY been wiped out and our resources taken. What we see today is merely what’s left over.
And perhaps we are the colonists who have grown from the seeds (DNA) planted by them?
I think I’ve read a few sci-fi books, or heard a prog album or two based on that concept...
That you can write—and I and others can read—your comment on Free Republic suggests that our planet has not been “wiped out.”
Unless the aliens were extraordinarily sloppy and inefficient (which would contradict their resource-gathering capability needed for interstellar travel), Earth’s resources and the elemental isotope distributions we see today are not “merely what’s left over,” but what this planet has had since the beginning, supplemented occasionally with some comets, meteors, and meteorites.