Okay, so now I believe I get your point: It's not that Crean is a good coach and has achieved (we agree here), it's that if he were fired after his very recent good year, IU would be perceived as an unstable, unrealistic program, both vis-a-vis the fanbase and the administration.
Every fact you site is accurate, but the facts you site are not the only relevant facts, and if a high-level candidate (Donovan, Bennett, Archie, maybe even Collins) has the inclination to explore the IU job, they will look at ALL of the relevant factors. They will undoubtedly understand the reality of Crean; that he is a 'quirky' (at best) personality that has huge potential to wear out his welcome. That Crean has a below .500 in-conference record over a large sample size of nine years, that IU is currently 13th in conference, etc. They will also understand the quite good reputation of AD Glass, though admittedly that is my anecdotal impression.
Glass has not willy-nilly fired coaches; Wilson got five years and was dumped to prevent real lawsuits and get out in front of abuse of injured players issues after having been previously warned to not cross that line. Crean has had nine years.
A realistic high level coach (not Self, Izzo, Wright, etc, and only Donovan if he is not happy in the NBA) will look at the entirety of the situation, and I stand by the points I listed as positives for IU: passionate fan base, high expectations, one of the best conferences, very high-level facilities, a big recruiting budget, a huge paycheck, to be at a school where basketball is the highest priority sport, and a history in the sport, not to mention a well-stocked cupboard of players.