Ask yourself, hypothetically, if Bergoglio for any reason were not pope right now, if five influential Cardinals stated that the See is vacant and called a conclave pursuant to the rules of Universi Dominici Gregis, what would happen?
I suspect we would have a validly elected pope in short order. No Bergoglian would dare to go, as it would concede the point that B is not the pope. It would avoid any controversy between the non-abdicationists and those holding to one of the other theories, leaving it for the new pope to definitively pronounce. And hence any pre-Bergoglian Cardinals who show would be valid electors. New pope, persecution of that pope and the Church, but a pope and and no more doubt. I know God has a plan, but He uses men to assist in His plan, does he not?