No. Everwhere ancient monsters are taking back temples and casting their shadows over the land. It is not a literal darkness, nor does it have the inter-dimensional qualities of the twilit. Darkness is merely the state of the land. That will become more clear as the story progresses. Also it's not to the point where towns and villages are being abandoned. Just to the point where outside kindoms are flooding into hyrule, which is also starting to see the same signs other kingdoms that were overcome have seen.