This is so easy to explain and everything I'm about to say has been backed up by certain members of the national media who actually focus on cfb and aren't just talking heads that dable in many sports:
1) Michigan gutted it's S&C staff in 2018...fired everyone because we were soft and had too many players going through the motions. Harbaugh hired this guy Ben Herbert who you might of heard of as he was Bert's S&C guy at Whisky and followed him to Arkansas. He all of a sudden became available in 2018 and Harbaugh jumped on it. You guys know exactly the importance of having the top S&C guy (see Doyle) and know these are the coaches that spend the most time with the players during the entire year setting the culture. We backed Herbert up by investing millions into our weight room.
But you guys also know this does not change things overnight and needs other things to align with it ..
So
2A) Once the results of Ben Herbert started to kick in Harbaugh dumped Don Brown (the DC). Brown was a statistically very good DC and innovative in his own way. However, his style couldn't get Michigan over the hump as it was soft up the middle. He brought in Mike McDonald who in three years went from being a one year wonder at Umich, to becoming the DC for The Ravens to getting the HC job with The Seattle Seahawks....do you honestly think that fast a rise happens because of sign stealing or maybe he was that good (you realize NFL teams vett before hiring HCs)? But...but...he was only there for one year...enter Jesse Minter who came from the same coaching tree (The Ravens) and was actually neck and neck with Mac, when Harbaugh was picking which of his brother's assistants to take, before Minter took another DC job prior to Jim deciding.
I have to chuckle a bit because I literally had to explain to this board that losing Coach Mac wasn't going to cause the fall off you guys thought...I mean you guys were predicting 8-4...one guy even claimed that Michigan would drop back to it's NORMAL 7-5...I had to explain to him that Harbaugh had more 10 win seasons than less than ten (while at Michigan) but that guy was as hard headed as you seem to be...you guys gave Mac a ton of credit for 2021...this is before we even brought in Stallions on staff btw...and he deserved it which is why he was quickly called back to the NFL...but we brought in his clone who also had a year of film from his clone to find new wrinkles to make our D even better...he had bigger, stronger and faster players to do it with thanks to coach Herb...
Transformation done on that side of the ball
2B) Michigan also changed the way it played O. I list this as 2 because it happened at the same time. I list this as B because at first it wasn't because we replaced our OC but rather diminished his role as Harbaugh took more control over the design of our O. Gattis' "speed in space" was flushed...it was a hybrid spread power concept that was more spread ...it didn't work for Michigan and was gone... Harbaugh also started giving a young assistant named Sherrone Moore some play calling responsibility which made sense because he was running Michigan's best unit (the OL...thanks in large part to coach Herb)...less than a year later Harbaugh got rid of Gattis' and gave that Moore guy the OC job....ever heard of him?
2C) Overall, in a short period Harbaugh changed his entire staff, in the process got quite a bit younger and brought in a lot of new thinking. Did he feel pressured to do so? Yes, what he was doing wasn't getting us to the next level despite having more 10 win seasons than not. But to his credit...he built this new staff around his own philosophy and then let them do their thing.
3) The players took notice. The players took control. They were tired of what was happening also. They leaders took on the Herbert mentality of pushing others to get better or get the F out.... I'm sure many of you have seen the post game (on field) interview from Cade @PSU 2021 where he said "no offense to teams of the past but they would have lost this game...this team is different"...that's why I will always appreciate Cade...he was not only apart of the change...he helped lead it...note: Stallions is still not on staff at this point
SO TO SUM UP
Michigan basically changed everything leading up to that 2021 season... EVERYTHING...well besides the HC...but everything else...but you don't get that...that doesn't make you an idiot...you just don't know...hope this helps you understand better
SO WHERE ARE THEY NOW?
Ben Herbert is now the highest paid S&C coach in all of FB and in the NFL
The guy he replaced finally landed at Bowling Green
Mike McDonald is the HC of the Seahawks
Minter is the DC for the chargers
Don Brown went for one year to the U of Arizona before going to Umass
Sherrone Moore is the HC at Michigan
Former OC Josh Gattis has now been fired from two jobs and is a figure head OC at Maryland under the real OC (HC) Locksley
So do you still think the only thing that changed is Stallions?