I think the concern about diagnosed (i.e. noticeable) concussions is a valid one, but it's not the likely end to the sport of football as we know it. Concussions get the headlines because the symptoms can be so dramatic and the plays that caused them can be shown on TV over and over again. The real danger is the idea that it's the little hits (that happen hundreds of times a year to every football player above the age of twelve or so) that might lead to severe symptoms years later. When it's accepted that the simple act of a kid's helmeted head hitting the ground or another player over and over again causes minute brain damage each time it occurs, you can bet that parents will put a stop to their child playing football. Wait and watch the what happens if the Surgeon General equates the damage to young brains from the repeated typical contact in tackle football to drops of water eventually wearing a hole in concrete.
We can wail over the perceived lack of toughness in today's world, but that won't salve my soul when the game I love goes away. It doesn't take much litigation to change things. Try to find lawn darts in the toy section or a child riding a bike without a helmet. The phrase "won't someone think about the children" has become a mocking line in our society, but the thought behind it holds tremendous sway with today's parents. I teach elementary school and you can bet not a single one of the kids in my class would be allowed to play organized football if society accepts that doing so presents an inherent and likely danger of eventual brain damage. Sissified society or not -- real threat of brain injury or not -- public perception will rule. And if youth football dies, so does college and professional, at least as we know it.
The real issue is not the one hit that causes a TBI. It's the thousands of little hits in youth football that don't seem to matter at the time that are beginning to cause real concern.