Both of you are wildly, wildly underestimating the luck factor involved in a single-elimination tournament.
Yeah, Stevens gives every appearance of being a great coach, and yeah, Butler getting to the title game 2 years in a row is probably the single most impressive performance by a non-power conference school in the last 25 years, at least, but the idea that Stevens was going to keep doing those kinds of things had he stayed at Butler is almost certainly wrong.
Butler's winning margins after the 1st round in 2010 were 2 (over a 13 seed), 4, 7, and 2. The next year, it was a 2 point win in the first round at the buzzer, 1 on a freak play where 1 seed Pitt fouled on their own missed FT with less than a second left in a tie game, 7, 3 in OT, and then they drew Virginia Commonwealth in the FF. Incredible run, but also a huge luck element involved, one that almost certainly wasn't going to be sustainable. As (and people tend to forget this) Stevens himself proved, because he coached 2 more years at Butler after that, missing the tourney in 11-12 and losing in the 2nd round in 12-13.