I agree with the general sentiment (don't hire a guy who failed somewhere else), but it's not true that they never work. Gene Chizik and Ed Orgeron were both retreads who won national titles. Chizik is complicated because he wasn't fired by ISU, he just had a terrible record and he's probably the worst coach to ever win a natty, but still.
On an NFL level, Bill Belichick was a retread (failed in Cleveland) and he's the greatest coach of all time. Pete Carroll was a failed NFL coach when USC hired him. I think the odds are against a retread (shockingly, Mike Locksley appears to still be an unbelievably terrible coach; also see Charlie Weis) but every hire is a crap shoot.
some very good points, but one big key
belichick and carroll learned from prior mistakes and made changes.
chizik was somewhat of a one-hit wonder and eddie o needs to prove he can win without a certain assistant on offense. he lost to nichols state for goodness sake
this is where we find ourselves with gary, the defensive staff, sonny, doug, anderson, and kill. have they learned from their mistakes or are they still showing systematic arrogance and trying to do things that aren't working on the fleld
losing isn't the issue as other have stated on this board, but how things have played out. the defense is historically bad against the run and giving up big plays at a rate surpassing every other big 12 team and most of college football. consider that two of the four teams they have played are a methodical isu team on offense and ksu with a true freshman quarterback and that isn't good. especially when you consider that ok state, tech, and wvu all have shown the ability to move the ball.
the only consistent pass rush is an undersized true freshman and the defensive ends and linebackers have been terrible against the run
pass coverage we see the same issues again and again and again
offensively we are back to no identity, a grab bag play calling approach, an over reliance on trick plays and odd formations and note that as more and more teams are getting film the offense seems to struggle
a "retread" coach who has learned from their mistakes and experiences can be very valuable and successful as you pointed out, but ones that are going right back to the same patterns only bring the same result to their prior parting with the program