This year they are the youngest team in D1 basketball. They also gave up a late three to Wisconsin from around 45-ft. They missed 3-FT's down the stretch of a game yesterday. Those fall and they don't give up the 45 footer, they win the BT outright, not sure how that is underachieving.
Coaching does contribute to underachievement, Raveling proved that, he could assemble talent, but well coaching was another story. I don't know why you think that talent is the only thing a program needs to be successful. You can look at the Fab 5 as failures, but getting to the point they did isn't easy or everyone would do it.
Ellerbee was a terrible coach and he cheated to get those guys as well, Michigan should be known more for scandals to stockpile talent than being underachievers.
Amaker was a solid coach with not a lot of talent.
Your point saying that they are underachieving has no basis. You say oh they put all their money in FB, so how is that the BB program's fault? You also have to have coaches that accept the role that their program fills in the pecking order. FB rules at Michigan, but David Brandon is changing that thought now, look no further than the Crisler Center, take a trip and be amazed, that is all I can say.
Honestly answer this question: What coach have they had that you can say has been truly a great coach, or even a better than average coach?