The Big Ten was 10-9 in this year's NCAA tournament, so it won more games than it lost. On the other hand, I think only Maryland and Rutgers and Wisconsin outplayed their seed, and those were all 9's and and a 10 who only advanced 1 round past their seed. Michigan State had a coin toss loss to UCLA in the 11-seed play-in game. Michigan, Illinois, Iowa, Ohio State, and Purdue all failed to advance to where they were seeded to advance, with Ohio State and Purdue suffering painful 1st Round losses to low seeds. If the Big Ten met expectations going into the tournament, there would have been 4 Big Ten teams in the Elite Eight and 2 going to the Final Four. It is clearly safe to say the Big Ten underperformed in 2021 NCAA Men's Tournament, which was made even more disheartening by failing to have a great performance when the whole tournament was based in the mid-point of your geographic footprint.
In hindsight, the limited number of non-conference games contributed to a failure to properly evaluate league strength. and then correlate that to individual team strength. The Big Ten was still one of the Top 3 or 4 conferences, but it definitely was not a runaway top conference that warranted 4 of the top 8 seeds overall. Obviously, the PAC 12 was underrated. Meanwhile, the ACC was not just weak, but historically weak and it look like the Big Ten winning the ACC-Big Ten challenge helped the Big Ten's prestige when it really shouldn't have counted as much with the ACC probably not being a Top 6 conference in the power ratings this year.
This might be what seeding might look like with a reevaluation:
Michigan - 1 to 2 seed
Illinois - 1 to 3 seed
Iowa - 2 to 4 seed
Ohio State - 2 to 4 seed
Purdue - 4 to 6 seed
Wisconsin - stay at 9
Rutgers - stay at 10
Maryland - stay at 10
MSU - stay at 11
Who's knows? Maybe a better fit with the seeding would have helped teams advance further. There seems to be something about playing teams you know about or have tape on, which might be an advantage some of those low seeds might have in those early round games.