Unfortunately, I think the motivations are complicated, the reasons are varied, and the situations are unique. Chris Anderson posted a insightful answer as to why young people are leaving fundamental churches, suggesting that the question itself might be the wrong question. Here is an exerpt from his answer:
My two cents? Kids are leaving their churches because the churches are unhealthy, not because they’re too conservative. Sheep who are shepherded well don’t tend to wander. Most don’t, anyway. So rather than blaming young people, or Christian colleges, or music, or John Piper, or Calvinism, labor to have a healthy church. And rather than preaching on why people shouldn’t leave, give them reasons to stay. Take care of sheep. Endeavor to be a good shepherd. See worship as a call to adoration, not a call to arms. Exalt the Chief Shepherd. Minister grace.
Make sure you read the rest of his article.
Personally, I'm glad the problem is getting noticed and publicly discussed. For too long it has been denied or ignored, hoping that it will go away. Recognizing that a problem exists is always the first step to solving it.
What do you think the problems are, if they exist? If they exist, should they be solved? If so, how?