You posited two concepts.
One that it is impossible to regain a pope when all Cardinals have apostacised.
Two that I am a protestant.
First of all it is not beyond God to provide what is needed to restore a pontif to the world in a situation that was in many ways unforeseen by man. He has done it before.
Secondly, I would suggest that those who follow the Novus Ordo have made themselves Protestants in so doing. So called Paul VI invited Protestants to the so-called Vatican II council in order to destroy the Mass and to Protestantize it. Only a true Catholic opposes the heresy of this anti-pope.
Sedavacantists have merely sought a more realistic ground for remaining true to the One Holy Catholic Apostolic Church. We attend the same Mass celebrated for over a thousand years, and offered by priests ordained in Apastolic succession.
Ok that's an answer I guess. If it works for you great but I'd note if I were you that one of the primary tenents of the Faith is that God (the Holy Spirit) works with and through His Creation to effect real change in Man (his salvation).
The Sacraments for example. He chooses to work with physical realities to dispense His saving Grace.
So it is also with the Church Herself. He has chosen to use mere faulty men as instruments of this Grace. Indeed, specific to our "chat"'here, He has revealed that it is His will that a college of Cardinals elects Popes.
Now it's certainly possible, just as anything is possible, that God may change this method in the future but here's the rub: He will never contradict Himself and this means the only way this change in method (of electing or selecting Popes) will come is THROUGH the Church in the first place.
This means that since the Church has not definitively said that "we won't use Cardinals to elect Popes anymore", no Pope in the past (since at least Vatican I) no council has said that, then the method has NOT changed and cannot change until God changes it THROUGH the Church. This is the fundamental Catholic position. That God works through His Church, He doesn't work to subvert HIS OWN CHURCH! To believe that quite frankly is heresy.
The gates of Hell have prevailed against the Church you believe in. If I were you I'd take the advice of your own screen name.