Based on watching the trend for 20+ years, of everything, I feel the most obvious reasons are not so obvious - free choice in your occupation and observation of what that occupation impacts. I say this becaus I have 3 daughters all in HS presently. Each excels at computers but has opted not to go into IT in any way shape or form based on these 2 criteria.

The first point, free choice, is fueled by the information age in providing information about different career options available and where they will lead and your quality of life. They have grown up in the infomation age and are using it to their advantage.

Now a bit about the second point. They have watched myself and friends and been a part of our lives and seen the type of comittment needed at times. There is usually a chorus in unison of "that sucks" quite often. So, they know what it is about almost first hand. This is learning by the observation of others.

We all have to remember that "The only constant in life is change".