"not require hospitalization"We'll probably never know (and honestly it's none of our business), but I'll always be curious about what happened between Tuesday and Thursday that resulted in such a sharp decline but did not require hospitalization. I suspect she either died suddenly and the earlier statement was just to give us all time to prepare, or else she had a terminal illness that they were managing quietly.
Maybe she wanted to die peacefully and at home and she refused hospitalization when in a critically condition? My father had made a patient's provision, in case he wasn't able to make his own decisions anymore. I could imagine that the Queen was the kind of person who wanted to have full control over this last chapter in her life. Today's medicine can keep you alive for a long time, even when you're in coma with few hope that you gain back consciousness. Imagine what this means in the Queen's case? Instability of the monarchy.