It is too late for that. The time to have done that was when it was just Kaepernick. If they show the crowd and you hear them booing, you will know the BLM contingent is at work. If they eliminate the anthem altogether, you'll know it was because of lack of respect and will still be pissed off. I frankly think the NFL has let it get out of hand and have probably lost fans that will never return.
I don’t believe it is too late. Without promotion in the form of a public stage the brainless young twits on the HS football/basketball teams will very soon lose interest because it will not be seen as “cool” any longer. The “Look at me, I’m just like the pro’s” angle is gone.
I would take a bet with very long odds that at any football game the cheers when the Anthem is played will far, far outweigh the boos from any blm creeps even bothering to go too the game.