That the moon had a full eclipse
For all the chest beating we do about summer being a platform for the players, we must concede the necessity of teams. Though the dash for scholarships is an individual pursuit, teams give the whole evaluation period context. Since basketball is, after all, a team sport, prospects are judged with regard to their fitness for joining a given team on the next level.
Not to mention the many things that teams are inherently good for -- learning to cooperate and coexist, learning to trust and be trusted, to name a few.