Sectoids got the best deal. They were chubby little gremlins doing grunt work, they didn't even have mouths, now they all look like chads.

What if we never domesticated anything but just have some kind of telepathic/telekinetic field that domesticates things around us, subtly and near unnoticably moving genes in a way that benefits us? What if this fields size is exponentially related to the amount of humans?

What if there was no invasion, but a desperate attempt to save the universe and evolution, which eventually failed when the invaders got exposed to the field at too high a strength?