It might be possible that the Supreme court is delaying taking action on this to build more precedence. Bump stocks and pistol braces are in the pipeline of consideration. An optimistic view is that they want these 3 to come to the court at the same time to smack them down and put them to rest. When a circuit court makes a decision it often times does not affect other circuits until it goes to the top. Plenty of chess gets played by the court and the maneuvers are not in a straight line. I'm disappointed but hopeful.