Good post, infielddad.
I believe the time demands of a sport also help kids stay more focused on what they need to do off the field. The discipline required to keep up with classes, school work, baseball and conditioning/lifting is something that will serve them well in life, too. They come to understand what it takes to excel on several levels. The coach at my son's school says that area employers will often call him if they're looking for employees because his players have already learned the meaning of hard work while meeting goals.
To me, the structured environment is a positive, not a negative. Not only are they getting to continue playing a sport they love, they're also getting an education in the process. My son talks about some non-athletes in his dorm who do nothing but play video games when they're not in class. Hey, free time can be overrated. All that said, he still has a little bit of a social life with his teammates and friends.