It has happened before in human History. And the results were so thorough that our modern science can’t seem to find the cause of the vanishing act. What killed off the Easter Islanders? What happened to the civilization which built Gobekli Teppe? etc.
The number of people alive today dwarfs the total number of people who have ever lived before in history.
If 9 out of 10 people were to die suddenly there is no way that the bodies could ever be disposed of by the survivors.