Not because of ill health surely? Ill health and slowly dying more or less in public are an ancient feature of the papacy. This is perfectly natural in a religion primarily concerned with life after death, which preaches its availability to all, or to all who believe and behave in the ante-chamber of life on earth. Paedophilia, theft, fraud, jealousy, cruelty, abuse, intolerance and denying the means of safe sex to prevent the spread of a terrible disease, are just a few of the behaviours regarded in the world outside the Roman Catholic Church as depraved, shocking and wicked. Most are crimes.
Yet these are the activities which define the modern Catholic church and its secretive Vatican state. Neither the organisation nor the verities it preaches can any longer be regarded as good or right or worthy, if founded upon such a breakdown of the integrity of thought and deed. The Pope remarked, as he explained his decision to step down, that it was as if the Lord were sleeping.
The Pope stood down because he lost his faith, not perhaps in God, but in the Church he headed any longer being a worthy instrument of divine will. In truth Benedict feared that God had walked away. Maybe in resigning he signalled his intention to follow Him. It will be up to his successor to organise a grand reconstruction in order to get them both to come back.