Actually the lawsuit was that they were insisting concussions left no permanent damage and were denying post retirement health benefits for that long term damage. Nobody really said anything about preventable, cause it’s a contact sport, you can’t prevent them all. And they settled out of court, so technically nothing is established.
The protocols they play under now prove that the NFL has the ability to reduce the occurrence of concussions. The reason they settled was they didn’t want to risk being proven negligent by not addressing the situation sooner. I would assume they still have the same concern. I know if I sued them I’d be overjoyed with an out of court settlement.