You're suggesting you the Pope is lying? Is it not reasonable to believe that a mid 80 year old guy can't keep up with the daily routines and would prefer to have the respect to hand the position off instead of diluting his duties until he passes on?
Just wondering. Sure, there are issues and maybe he feels he doesn't have the internal controls that he wishes. It wouldn't seem far fetched to me to see younger people manipulating an older leader for whatever cause.
In fact, I would say that he has shown dignity and respect for the position by stepping down. Hopefully that message resounds elsewhere.