That's exactly it. A lot of the 49ers defensive success last year was because they got a huge amount of turnovers. They led the league with 38, and everyone said they wouldn't repeat that same success this year. They were right, and the 49ers only had 25 this season. Compare that to the Bears who had 44 turnovers this season, with 9 going for scores, and it's easy to see those historic numbers are probably completely unsustainable because of how random turnovers are. It has nothing to do with forgetting how to punch the ball out or pick off a pass.