So Fury should have "killed" Maria Hill and then the Avengers would have come.
Also, the species of the planets of the ninth realms should have know this, considering that the darkness was in Asgard, it would have been all over the ninth realm.
They haven't been told yet. This shit happens all the time and we mere mortals are rarely aware. To Thor, 'tis but a mere skirmish.
So the world is being destroyed and the avengers don't know?