They ruin everything!
That said, I am conflicted. My son played football (flag and then tackle) from first grade and now in college. It's a rough sport, for sure.
So, for that matter, is basketball and don't get me started on cheerleading.
My son sustained a concussion on the field. It was seriously scary.
And while we have not really encouraged it and didn't think we were crazy "football parents", we did allow it and, frankly, he loves it.
Over all and on balance, football has been a positive in his life. I'm glad he's not playing DI and I'm very glad he has no realistic chance to play after college, but football was his ticket to a top tier school where he is double majoring in Physics and Chemistry, maintaining an A average, and will intern for NASA this summer (no really!)
I support starting tackle later, and reducing the number of "micro hits" players take. My step-dad played DI football and bemoans some of the changes sometimes, but also wants his grandson to graduate with most of his grey matter intact.
It's complicated.