According to this article on the Greek Archdiocese’s website, it’s about intermarriage. Excerpt:
In a startling find, statistics disclose over 60% of Greek Orthodox families of the last generation and 90% of Americans with Greek roots are no longer in communion with the Church. 

It is a concern shared by learned religious leaders who understand the need for a compassionate outreach towards intermarried families with sensitivity to differences among intermarried couples and the problems they face as a family. In the transition, as each population passes into successive generations, growing numbers of families move further from their origins, with the probability that our beloved Greek Orthodox Church in America will become moribund in the very near future.

Anybody else see what’s wrong with this? Intermarriage only makes these families less culturally and ethnically Greek. It need not make them less Orthodox. The fact that the Archdiocese conceives of this as a problem of intermarriage, and not as a failure of catechesis and evangelism, indicates a basic misunderstanding of the problem. If you acculturate your people to think the experience of the liturgical life of the Church is pretty much The Tribe At Prayer, you shouldn’t be surprised when their loosening of tribal bonds through intermarriage results in a falling away from the Church. I have two Greek friends who were raised Greek Orthodox but no longer are (one’s Evangelical, one’s Catholic) because, as they put it, Christianity was all Greek to them growing up.

All churches in this country are facing a crisis of the young falling away. We need not make the situation worse than it has to be by misdiagnosing it. Or is there something I’m not seeing here?