“I assume that the posters were talking about the Yeshiva/Chasidish world. I think in the modern orthodox world a lot of kids “drift” away.”
Even that is them being pushed away. They are presented with a system that is wildly hypocritical, devoid of value, and not all that enthusiastic with Torah and Mitzvos to begin with. Is there any wonder that when they are shown the alternative they jump?