It isn't the real world. It's a youth sport. The reasoning that a kid absurdly older for his grade because he repeated grades isn't truly special or good to be blowing up kids much younger and less mature. There are some very talented kids who can play up ages and grades, and then here are the other 90%+ of the kids playing the game. Modeling the sport for the wants and needs of only 5% or 10% of the people who participate is the reason why sports like lacrosse struggle to grow after an early growth phase. Lacrosse could easily grow to be as large as youth baseball or soccer, but has no chance to structured as-is. There are only bad arguments to preserve and protect this grade based scheme to allow bargains for kids to play down. There isn't anything positive that comes of it.