Yes, other sports at the junior high and high school level have this rule too. They do it to prevent over-aggressive coaches from scheduling earlier and earlier and to help keep things fair between the schools. I don't have the information about other clubs but I do know that in Salvation Army football, they have a start date for practices that has to be abided.
Look, I am just saying that if we leave it like it is, there will always be some club or some tournament that wants to schedule earlier and earlier forcing others to do the same to stay competitive. Yes, a club can start later but then they get the pressure from their parents wondering why they didn't start earlier like other clubs. And then those kids start competing in tournaments where other wrestlers have already gone to a few and so yes, they will have a slight advantage.
The point is, I personally feel that the long season is one of the reason's we lose some of the wrestlers and their families. Yes, they can quit early but many do not. This is what can lead to burnout. Again, is there really a VALID reason the season has to be as long as it is? If there is, please share it with me.