Ultramontanism, the radical commitment to the current teaching of the Pope, is simply repackaged Modernism. Any attempt to move away from Scripture and authentic Tradition leads to an abandonment of Truth Himself.
As seen in the Church Fathers, even if St. Peter is the Rock of Matthew 16, the modern papal doctrines do not follow. Rather, a proper equality of bishops is taught by the Sacred Scriptures and the Church Fathers.
The greatest problem in the Catholic Church today is Modernism. While usually a concern among Romanists, it is a chiefly Protestant concern.
Just as a civil kingdom is a perfect society, so is the kingdom of God: the Catholic Church.
Anglicanism expresses the authentically catholic view of the Eucharist, grounded in Scripture. Neither reductionistic Zwinglianism nor excessive Romanism.
While it is easy to simply accuse the Ecclesia Anglicana of being disobedient in the Reformation, she actually understood the needs of her times and the demands of virtue.
While it is common to think that King Henry VIII started the Church of England, it actually has deeper roots than that.
Defenders of papal supremacy and the Solus Petrus hermeneutic often point to Jesus giving Peter the keys. However, the text of Scripture shows that Peter isn't given the keys separately from the other apostles.
While Rome tries to the appeal to the Scriptures to justify her supremacy, she has to contort and add to the Scriptures to make it work.
Seeing the main contradiction of papal supremacy, we see the further implications of embracing this contradiction: the Church is no longer a perfect society.