be expected to score on every (limited) possession after sitting cold for 8-10 minutes of game time (prolly twice that in real actual time sitting) either.

As with so many things, we have two extremes when the answer lies somewhere in the middle. And every game may need to strike a slightly different balance. Play the same way every week and you get predictable and easy to beat. Sure, you may keep the points low and may run huge amounts of time off the clock. But you don't give yourself many opportunities to win either.

Could the defense keep the overall same philosophy but mix it up on occasions to keep offenses on their heels? Probably.
Should they blitz every down? Probably not.

The Utah game was a very good game plan. Across the board. Tough opponent. Mix it up from the start and give them something they aren't used to seeing on film. Bring the heat to keep the offense from settling into a rhythm and gaining confidence early. When a solid lead is established, go into more of your conservative bend but don't break defense. Lean on the crowd. Ratchet it up when the occasion calls for it.