It sounds cool but it's not supported by the lore all that well simply bc oryx does die. Ascendent hive only truly die in their throne worlds. At one point oryx had to make part of the dreadnaught (how do you spell that again?) His throne world. So we killed him in his part if the dreadnaught so therefore he is really dead. Again, these are cool ideas though.
You are assuming that we know everything there is to know about hive lore.
And that we have exhausted all efforts and met all conditions and so therefore he (Oryx) is dead.
But what if there's just one little piece of lore that we don't know about that could explain why he's alive.