User blog comment:Tiredman2/Mass Effect Plot Holes and Contradictions/@comment-5385713-20120824010850

I'm pretty sure there are still several uncharted islands on Earth, so the galaxy being slightly bigger, you know... it might have been missed before by other races, or just didn't care. Most races seem to have several colonies usually nearby their home planet, and they have been doing space travel for a lot longer, so they really didn't need yet another "garden" planet to colonize.