Not saying there are not many fallen away Catholics that are now protestants. But tell me how many former Catholic theologians, well-grounded in the Christian faith, decided Catholism was in error so they jumped to protestantism. I guess there might be one out there but I’ve never heard of any. Now there are plenty of former Catholics that were never strong Catholics to start with that become protestant. Hardly any were devout that attended Mass on a regular basis. That hardly ever happens. There’s literally hundreds of thousands of astute former protestants that knew the Bible from cover to cover that become Catholic. And none of them do it on the spur of the moment. It is always a well-rounded decision they came to after years of studying the Christian faith and praying a lot. Many former protestant pastors have converted, not too many former Catholic priests, unless he wanted to get married and couldn’t in the Catholic faith. That’s usually why a Catholic priest leaves the faith, and that’s not too many.
The following quotes are taken from the book by Richard Bennet, Far from Rome, Near to God: Testimonies of 50 Converted Roman Catholic Priests, Carlisle, PN: The Banner of Truth Trust, 1997. They are quite interesting and valuable since they give an insight to Catholicism from those who were priests in the Catholic Church and then left it to find salvation in Jesus.