Doing the job to the end of her life is the part of her coronation oath
that she seems determined to keep despite hardship, while fudging the
rest to suit the times.
The highest purpose of her reign appears to be making as little trouble
as possible in order to sustain the hereditary monarchy. If this has any
meaning for the supreme governor of the Church of England, only God
working through nature (or failing that parliament) can decide when a
succession takes place.
Her god has evidently changed his mind several times to make her life
easier since she came to the throne, for instance on the remarriage of
divorced people - especially within her own family - since the cases of
Wallis Simpson and Peter Townsend. Maybe he will let her off the gilded
hook of being the monarch somehow before she dies, but I doubt it.
Peter Stewart