There is a vast difference between eliminating risks and at least making an effort to mitigate them. Right now, the NFL isn't even acknowledging them, which is patently absurd. And it's equally absurd to argue that these guys know they're playing a violent, physical sport, so brain damage is just an inevitable outcome. That's as ridiculous as saying "Well, dude, you worked at a sawmill, you should've known there was a good chance you'd shear your right arm off."
The average career of an NFL player is 2.5 years. During that short time they can come away with serious and debilitating conditions that could hamper their quality of life. I don't see why it's so much to ask a long line of insanely rich people and corporations to put aside what would amount to a pittance to help take care of these people. Again, there are still many billions that they can keep for themselves.