It seems like such a simple solution. I don't know why they ever stopped using it.
You want people to stop making noise? Ask them.
No, they say? Ask them again.
They refuse to comply with your request? OK, hit the home team with a penalty.
Oh, listen. Is that the sound of silence?
It's how the NFL used to do it. If the home crowd was making so much noise that it interfered with the visiting team's ability to hear its own snap count, the quarterback stepped out from under center, turned to the referee and said, "We can't hear."
The referee then appealed to the crowd to lower the volume. After a couple of failed attempts to quiet the crowd, the referee threatened to penalize the home team, at which point the coaches and players of the home team gestured to the home folks to pipe down, and they usually did.
It was a system that worked. Unfortunately, noisy home crowds called the referee's bluff so often and referees were so reluctant to penalize the home team that lengthy delays resulted, causing unnatural breaks in the action and disrupting the flow of the game. It was, however, a system that ultimately succeeded to control crowd noise; it just needed to be more forceful in its enforcement.
It was a system that even included a safeguard against quarterbacks taking advantage of the penalty threat by continuing to claim noise interference. At some point, when the referee felt the noise level had been sufficiently reduced, he pointed the quarterback back under center, which meant play. At that point, the offense was subject to delay of game.
The NFL, however, was so concerned about the time delays the system was causing that it junked it and put all of the pressure on offenses to find a way to deal with the noise. The problem now is that the noise, especially in domed stadiums, has reached a point of intensity that offenses are incapable of dealing with it. The noise factor has now made for a competitive disadvantage that can not be overcome.
What to do? Well, I guess we could install microphones in quarterbacks' helmets, or we could just go back to the old way of doing it and ask nicely, then less nicely, then threaten, then penalize. We could do it that way, or we could just cut the cords on the microphones used to gather the sound, amplify it and re-circulate it through the stadium's sound system.