Agree that it this seems very school specific. In our large public, many kids seem to pull it off, but there is significant cooperation between the music teachers and the coaches. Conflicts are inevitable, but if enough kids are involved in both, as seems to be the case here, everyone works hard to compromise and find a way to work things out. I also agree that it is probably not happening with the kids who are on a nationally ranked team, no matter how flexible things seem. Those kids are driven and don't seem to have much time or energy left for other endeavors; they train and workout daily and year-round.
What I don't get is how the kids find time to do their homework, volunteer work, any jobs or chores, or any other clubs, etc. (clearly, we are not a family who does this- our DD thrives on busy, but there are only so many hours in the day).