Occam's papal razor
The truth was almost certainly more prosaic and sadder - Wilson had early-onset Alzheimers Disease. The early effects of this illness would have robbed him of his memory, his energy and his ability to do the job. His decision to resign was inevitable - by 1979 he was so deep into his Alzheimers that he needed to be dressed by his wife.
Matthew Parris in today's Times is worried by the Pope's unprecedented resignation:
I’m finding the whole story less and less satisfactory. Cardinal Ratzinger was not an outsider. This was not a job whose characteristics were likely to take him by surprise. He will have worked his way up by cautious conservatism and careful calculation. Nothing in his life has suggested an impulsive nature; nothing hints at a propensity to kick over the traces. He is not ill. He is not senile. He’s in good shape by the standards of the gerontocratic Catholic leadership. He has no family to spend more time with.
And suddenly — breaking all tradition but (more than that) defying the theological foundation on which his office rests, that a frail and fallible human is inhabited by the Divine Authority as a glove is filled by a hand — he leaps from the moving train, pleading fatigue. Shouldn’t a believer have left it to God?
The train hurtles on into the night. An old man rolls down the embankment. Something’s up. Something has happened. I have not the least idea what.
Pope Emeritus Benedict is nearly 86 years old. 45% of people over 85 have Alzheimer's Disease. Benedict watched John Paul II decline through Parkinsons and possible dementia. Would it really be so surprising that he shrank from inflicting a similar public decline into incapacity?