Why haven't Andromedan species come to the Milky Way?

We know the reapers operate on a cycle to take out species when they get a certain size, so presumably Milky Way species never get large enough to start seriously contemplating extra-galatic colonisation efforts.

So in the billions of years following the creation of the Reapers, why haven't Andromedan species come to the Milky Way? If there aren't Reapers or something similar in Andromeda, their civilisations should not be getting artificially shorted lifespans and so some of them must have at least contemplated it.  I'm am absolutely not suggesting the existence of Andromedan Reapers, as far as we can really say they are a Milky Way thing only.

Other than the RL reasons for the developers ("we never planned for Andromeda"), this is something that the developers will need to address in some form.

Maybe the Andromedan civilisations know about the reapers because their previous attempts to colonise happened just before the Reapers re-emerge from Dark Space and the colonists got wiped out. We know there are civilisations that died off (the Remnant). Perhaps (very "luckily") by some coincidence the Kett are the same "age" as the milky way species and just happened to be there to fill the void left by the Remnant suddenly disappearing.  Regardless, I have a feeling that the Remnant will be important in answering this question.