The goal is to put the most talent on the team. A lot of these kids are already known before the tryout begins. While it's great in theory to only put together the team based on a few hour tryout, why would they discount what the kids have shown over the years. You think they are going to cut one of the known best players in the area because they had an off day?

When you apply for a job do they only take the interview into account or do they actually look at your resume?