To keep it from being an obvious advantage to either team. Cant give Miller the catch and not the opportunity for the defender to be rewarded for the obvious strip. Also cant just assume Philly would have recovered it.
If the rule is changed, it shiuld simply be to replay the down. Which it likely will...
Ok, here is a couple of scenarios for you.
Mack blasts through in the NFC Championship game and clobbers Drew Brees on fourth down. Ball comes out yet the ref blows the whistle dead and says that he arm was coming forward so it is a forward pass. On review it is found that it was indeed a fumble but no one recovered the ball because the ball was blown dead because the ref thought he saw his arm going forward.
Scenerio 2. Jordan Howard, in the same game, finds a seam in defense and blasts into the secondary. He gets 28 yards in the final seconds of the first half and as he is about to go to the ground he is hit and the ball comes out. Fortunately the ref blows the play dead saying his knee touched before the ball came out. Review shows that his knee did not touch but since the whistle blew no one recovered the obvious fumble.
What about those two scenarios is different from the play yesterday? In all the cases the player hand possession of the football and fumbled. But in case one and two the ball is dead at the spot of the fumble while in the game the play was called an incomplete pass. The Bears lost a down and yardage because a ref blew a whistle. What if this 'rule' was applied on run plays or sacks? Using your logic neither above play occurred and should be run again. All because a ref screwed up. What if on the 'do over' Drews throws a TD pass and the Saints go to the Superbowl? Or if that run by Howard means no field goal and we lose by 2.
If the receiver receives the ball then he is a runner. He is responsible for maintaining ball security. Now because the ref screwed up and blew the ball dead that is too bad but it shouldn't penalize a team that made the completion. If the roles were reversed and it was a pass from Foles to Ertz I would have the same opinion. Both teams lost an opportunity in that play. But calling it an incomplete pass when it actually was is pretty dumb. Saying do over isn't an answer either since it was already established the guy was a runner, not a receiver anymore.