NFL will go to flag football soon.
The demise is scripted out already. One state will stand up by 2016 and present evidence of concussions causing damage to high school players. It’ll take two years but they will determine that both ice hockey and football have to terminate. A year later...two more states outlaw it...even at the college level. These states will be ones without NFL franchises.
So a debate will occur. Meanwhile, in the states affected, there are no more kids recruited for football. The decent kids who had chances in these three states? Their parents move to southern states where the kid still has a chance. By 2025, another four states will join, with California outlawing high school football entirely by that point. It spells the eventual demise of all college football in the state.
Somewhere by 2030, the NFL comes to an end. With retired players in their 40s and 50s carrying out lawsuits...the NFL can no longer operate at a profitable level. It ends with a great curiosity over what sport can survive and take over in the fall?