The ones that left for personal reasons, or anger at the Rc church may come back, but no TRUELY saved/born again comes back.
The problem is everyone that left for a non Catholic church is lumped together as if they were from one loaf.. Some leave because they are converted to Christ, some leave because they leave, no spiritual reason or experience.
And some leave, then come back, because they discovered that they lost Christ by leaving.
(See Jeff Cavins' biography, for example.)
Jesus was a Jew and the first convert to the Catholic Church; the Church Christ built. The "denominations" and other cults sprang forth 1500+ years later.
Beware of false prophets.