One thing to remember is fan expectations play a role in all of this. If the fan base has totally accepted the fact that "we can never compete with XYZ" the AD is more than happy to keep a lame product each season.
Iowa, Indiana, Purdue, Minny, Wisky, MD, Rutgers, NW and so one, the expectations of the fans are so lame that the AD doesn't have to do anything. So those teams MIGHT have that good year here and there, that "magical" 9 win season or that season where they pull off a great upset but still crap the bed vs other lame teams.
In the Big Ten you probably have 4-6 teams that actually want to win and expect it.