As for Michigan, since we finally have LBs, that could be true. Though the 2016 DL was filthier than this. Taco/Wormley/Gary/Winovich at end. And then it was Glasgow/Godin/Hurst and someone I'm forgetting. That was a DL for the ages. I mean, Hurst may have been the most impactful player on his few snaps AND HE WASN'T EVEN A STARTER.
The LBs thing might make you right, though. The 2016 LBs were "fine." I still remember how that season began. That team could have played with a starting DL, Peppers, all DBs and still gotten those early shut outs. Obviously offenses would have changed their calls if Michigan were only using 9 guys on defense. But what I mean is that, with how well the DL+Peppers were playing, the LBs didn't even need to be there.