They Gophers actually tied for 12TH out of 18 in 2024-25. Only 2 teams finished below them, but that's the not same thing as being 16TH.
"Barely" worse is a relative term. Also the Big 10 is now structured differently than it was during Johnson's first 3 seasons in Minnesota.
Missing the Big 10 Tournament say in back to back seasons would be more than "barely" worse, in my opinion. I hope that does not happen, but certainly a feasible possible outcome for whomever the new coach is. Again, I am not saying it's wasn't the right time to let Johnson go.
I would suspect if any of the 3 current Big 10 teams that missed out on Indy this season (Nebraska, Penn St or Washington) fall short in 2026, they will be looking for new Head Coaches about this time next year.