Catholicism, with its reliance on Tradition, was able to resist this subjectivism in thought but was not immune. Liberal Protestant ideas started to enter into Catholic academic thought through Modernism in the late 19th cent. But where Catholicism differs with Protestantism is the existence of an authoritative Magisterium that was able to resist this movement and Modernism was condemned by Pope Pius X. It was, however, able to make a comeback after Vatican II. It could even be said that it became dominant at the academic and popular levels. Again, however, it was never able to change the dogmatic teachings of the Magisterium. The spread of Modernism (i.e. liberal Protestant thought) was more from a neglect of discipline by the Magisterium rather than by its adoption. Today, however, even on the academic and popular levels there is a return to orthodoxy.
As a Catholic I would call this preservation of orthodox teaching at the Magisterial level a result of the protection of the Holy Spirit. A non-Catholic might take a more cynical view and note that if the Catholic Church would ever deny a dogmatic teaching that it had declared in the past that it would deny its very claim of infallibility and thus its very nature. Thus such a cynic would say that the Catholic Church cannot deny a previously defined dogmatic teaching only because of self-preservation. In either case, the Catholic Church has a bulwark against the spread of Modernism/liberalism that Protestantism does not.
Really, we agree on many facts, but not all. We do not agree on your Rome-centered rubric of history.
In Romanism - sola ecclesia - or sola magisterium, you simply outsource belief to Rome. You can refer to that as a protective arrangement and it is one form. What Romans never consider is what they lose by this arrangement. How could they and support the dogma of sola Rome? It must remain perfect to the roman mind, or the story is broken.
Rome resisting liberalism? The evidence in her parishes contradicts this. In Belgium alone, more than 80% of Romans never darken the door of a church. Here in the USA, many studies show Romans do not believe the teachings of Rome.
Protestantism is a broad word the way you wield it. Groups of liberals are cut off like cancer from Bible believing Christian groups - yet it serves the purpose of many Romans to set them up as straw men. It could be reversed easily. We could call all the crazy offshoots of Rome “Catholics”.
Sola Scriptura - the belief that inspired Scripture is sufficient for salvation, maturity and doctrine - has led to deep faith, the evangelization of the earth, ekklesia around the world, etc.
Protestantism doesn’t “seek to place authority in God alone.” It recognizes that His authority is over us. His Word is the last Word in all matters of faith and practice.
Cancerous offshoots are cut off. This seems to please Romans as they get to raise the number of “protestant” denominations. They eventually have to merge to keep their buildings as they die off. They die off because they abandon the One Source of Life.
The Christians who continue to know God, trust His word and follow Him continue on in pursuit of all He desires. Their ekklesia continue to grow. Our one ekklesia baptizes between 120-160 new Christians each quarter. Not born into the faith infants. Individuals who were far from God, tattooed, pierced, etc. - individuals who heard and responded to the Gospel and want to announce to the world that they are now a follower of Christ. They are now lives changed by Christ.
It is always and forever about His Glory, His Gospel of Grace, His Bride and His Body.
It is never about churches, denominations, etc.