Remember Harry saying no one wanted the "top job".
Do you think that is true of Charles, or do you think its just the younger generation who feel that way.
If Edward VIII had not abdicated, I think the Queen would have been happy living in the country, breeding Horses, let Phillip become First Sea Lord (or whatever the top Admiral job is.) She would have just been Princess Elizabeth, Countess of Something (a bit like Margaret.)
Although Edward had no children, so I guess HM was destined to be lumbered, but not till the 1970's which would have changed every thing.