The flip side of this argument is if you can't raise CU's defense out of a ranking in the 100s you're probably a s**t DC. A mediocre coach could look like a hero here.
Baer found another job pretty quick, so I'm not sure it's quite the career killer you're making it out to be.
I said this job has a lot of career risk for a DC making a lateral move or trying to move up in the coaching ranks. Yes, a mediocre coach looks like a hero if the defense is turned around, but that is the high reward party of my point.
Baer went from some really big time programs in his earlier years to a really small program and was brought to CU by MM. He is now back at a small time program after failing at CU, so not the best example.
My point is that a high caliber candidate like Durkin, would have been taking a huge career risk by coming to CU. It would drastically slow his career advancement if he failed here. Instead, he's going to coach at the biggest program of all time under Harbaugh. He'll be a head coaching candidate within 2-3 years if UM has decent success.