Vatican I:
For in the Apostolic See the Catholic religion has always been preserved unblemished, and sacred doctrine been held in honor. ... [T]his see of St. Peter always remains unblemished by any error, in accordance with the divine promise of our Lord and Saviour to the prince of his disciples...
If V2 and the NOM and the V2 papal claimants haven't "blemished" the Holy See with error, then there's no such thing.
This above is what Catholics have always believed, and which Archbishop Lefebvre himself restated.
You guys make a laughing stock of the Church for teaching this. So if the Apostolic See can go off the rails this badly, hey, maybe the Prots were right after all, or the Orthodox, or the Old Catholics, or even the Modernists. Many of you have as much if not more disdain for the prerogative of the Magisterium than the Old Catholics did.