Butler: The gateway job

Everyone I know was fairly startled to hear that Thad Matta was being replaced as the head coach at Ohio State. He's been very successful, and there were no rumors of his impending departure, while the timing, early June, was also quite unusual. It was no surprise, however, to see the Buckeyes go to Indianapolis and Butler University to find their next coach, Chris Holtmann.
Since 1989, when Joe Sexson retired, the only coach not to leave Butler for a better hob (where "better job" means a larger conference or the NBA) was Brandon Miller, who departed with a medical condition, and did not return after one season on the job. Let's run through the list.
First, it was Barry Collier, who, after leading Butler to their first NCAA tournaments in 35 years, left the Bulldogs to take over at Nebraska. Thad Matta (small world) then took over for a year before headed off to Xavier, where his tenure was also brief before getting the job at Ohio State. Next was Todd Lickliter, who took a job with Iowa after reaching the Sweet 16 with the Bulldogs for the second time. Brad Stevens outdid Lickliter's accomplishments by bringing Butler to the NCAA Championship game, losing both times, but securing a job with the Boston Celttics. After Brandon Miller was unable to continue, we had Chris Holtmann, who is now with the Buckeyes.
How did this happen? How did Butler become such a breeding ground of excellent coaches? Some of it must certainly be the location, in the heart of where basketball in nearly a religion. Heck, Hinkle Fieldhouse, home of the Bulldogs, is where Hoosiers was filmed. Naturally, an Indiana school should be able to develop great basketball talent. Not only has this happened at the 3 major conference schools, but also at Indiana State, Valparaiso and Evansville, but never with the sustained success that Butler has.
Valparaiso might come closest, but one can point to their reliance on the Drew family for that. And Homer never left, like the coaches in Butler's lineage. A lot of credit needs to be attributed to Collier, I would posit. It's easy to recruit big names when you have some initial success, and it's even easier to hire good head coaches when you can simply promote the talented assistant's that your departing coach hired.
Collier had post season appearances in 3 of his final 4 seasons at Butler, and had two very good assistants in his last few years: Thad Matta and Todd Lickliter. When Lickliter took over, he hired young, eager eyed Brad Stevens. Brandon Miller came back to Butler, he was the first coach since Collier not to be directly promoted after serving on the staff the season before. He had been an assistant at Illinois, and brought Chris Holtmann from Gardner-Webb to coach. By that point, the lineage and tradition of success started when Collier took over had been established. It was easier to recruit talent.
Oh, and do you know who has hired the last three head coaches? Collier is the athletic director at Butler, and has been since 2006. Bob Collier might just be a coaching genius, and one that doesn't get enough credit.