I remember Harbaugh mentioning something about not being able to make plays. I don't remember the words, but it wasn't clear whether he was talking about offense or defense.
he was talking about both i thought - basically that ultimately it comes down to who makes those plays in those critical situations and we just didnt make enough of them
i think that's also maybe part of why he decided to part ways with wink because as efficient as that defence was and especially on 3rd down (even when it was chopped up to hell), it's not a defence that creates many opportunities for turnovers or big plays and he talked explicitly about big plays and redzone success when talking about the offence near the beginning of the presser
so i think it was both sides of the ball