Isn't Ragnarok Inevitable and Necessary?
Both Odin and Thor have defined Asgard rightfully as the people and citizens. Heimdahl goes through great effort to save as many as he can and even Loki appears to understand why it is done. But the trailer for Avengers:Infinity War suggests something more sinister with Loki stepping over what appears to be the bodies of the final people of Asgard. Even in Thor's Scarlet Witch induced dreams he is forewarned that he is a Destroyer because of his power and he has a glimpse of I think four of the stones.
It is Odin's statement to Loki that in his birth right he was meant to die. Being that Loki is truly an Asgardian and has a complicated relationship with Hela might not the total destruction of all Asgardians be something that Thanos will execute that completes Ragnarok but also reconstitutes Asgard (unwittingly), like a total reset just without Odin?
The other anomaly was that Lady Sif was no where to be found and yet she perhaps survived to enable the Re-Birth of Asgard?