Balanced against how many people leave Orthodoxy annually for Protestantism or Catholicism or not?
This is sad, but I have yet to learn a good reason for such a move. Probably most Orthodox who become Catholic or Protestant were Catholic or Protestant to begin with and/or never really came to learn about, understand, or live the faith. Or, they were raised in an Orthodox Church and never learned about the Orthodox faith, perhaps because services were always in a foreign language and their parents and clergy didn't teach them anything outside of the services. We have countless stories of Roman Catholic and Protestant monastics and clergy that entered the Orthodox Church for reasons of faith and conviction after studying the Fathers and the early Church. Have you ever heard of an Orthodox priest or monk becoming a Protestant or Catholic because he read the Fathers and Church history and was convinced of the need for Papal Primacy or of Sola Scriptura?