sorry fellas, the first problem is that Chryst was born and raised in Madison. his dad was a Badger, he was a Badger, now he's the OC in his hometown which has gotta be on of the sweetest non-HC gigs he could have. secondly, i believe he has kids in high school still, so he may not want to uproot again and disrupt things for them. the third is the biggest: his personality. he may be an absolute genius with the X's and O's, but he's a reserved, quiet guy and not the energetic fire-it-up leader type of personality one might need to be the leader of an entire football team.
IMHO that is what got Bret the gig as our HC, with how he fired up the team in a 2004 game where BB came down from the booth and kicked the crap out of everything in sight and tore into his defensive players - and they responded in the second half with a shutout, and won the game.
note to someone above: Bielema was hired in 2004 as DC, Chryst 2005 as OC. BB was already named coach-to-be before he brought Chryst on.