But they keep playing because even the players on the losing team can get yards and catches and possibly a touchdown for their individual stats.
Yes, they keep playing and yes the second and third stringers get a chance to play.
Now it would be bad form for a winning coach in that situation to be faking punts and trying trick plays when he already had a huge lead. But you can’t blame a coach or player if he hands the ball off and no one tackles a runner.