I know running out the clock on offense is called the 4 minute drill. In a similar, but separate fashion, is this what the defense is trying to do?

I'm sure the D is never trying to let the opponent score, but perhaps the way they choose to defend an opponent when the Packers have a big lead says to keep everything in front of them (hopefully no big plays), so while it seems like a bloodletting by 5-10 yard chunks of short routes by the opposing offense, it keeps the clock going on completions, and if you want to take several minutes to matriculate the ball down the field, that saves wear and tear on my offensive players, and while you might score, we are not giving you any more than we are willing to let you have. We are looking at the play clock and counting potential possessions remaining in the game. Even if we let you score a few touchdowns and look like you are catching up, we figure it's going to take time off the clock for you to do that, and the remainder of the time we will run out on offense.

Do I understand the philosophy correctly?

Is it a philosophy that says, it's a long season, so let's play hard, but play smart and only worry about the final score, but not style points if we happen to shut out an opponent? I'm sure it takes more energy and possible risk to players health to play hard enough to shut down an opponent from the defensive side of the ball. I'm not saying the Packers D will always have that kind of control, but with a big lead, that might become the philosophy. It makes the D look soft in the 2nd half, but if it preserves some health and runs out the clock, and doesn't scare fans half to death, it's a workable philosophy.