We'll likely never know - coaching hires are like any other job, where a lot of factors are likely at play in the final decision.
The upside is Steve Miller is a great recruiter and a serious part of DU resurgence. He is mature, accomplished, articulate, loyal and has a strong hockey mind. He is certainly overdue for a chance to be a head coach. He's only interviewed for a handful of positions over the years.
The downside is he's earning at the high end of NCAA assistant coaches, likely above $100k. There is also the fact that because he's been working for Gwoz for about 20 years, he may not have as much exposure to different other coaches. He also lacks a masters degree, which hurts his candidacy for NCAA head coaching positions. Or for whatever reason, perhaps he doesn't connect as well with those who are interviewing him.
Whatever it is, I hope that he gets his shot someday...