I agree that is one issue that is a significant variable in explaining former Catholics, probably the most significant one. Most of my relatives who are no longer Catholic all had marriages in the Catholic Church that ended and when they remarried they went Protestant.
We have a hard core of people in our Church who never want to change ANYTHING, even the tiniest little bit. A good number of them want to go back to saying the Mass in Latin, a language understood by 0.002% of the world’s population.
Being Catholic entails having been baptized into the faith
There is really no such thing as a former catholic. No one knows that better than a ‘former’ catholic. They are usually not apathetic toward Catholicism. They profess hatred toward it, they’ll cite some wacky made-up rule about it they cannot abide by but they are Catholic
They’ll be judged as Catholic when it counts. They know it