Let's step away from the ledge re: Crowton last year...

The scenario after last year, for those who don't recall:

9-4, after the abortion that was the previous season.

Many were calling for Miles' head (a good number still are)

This season certainly didn't look promising, a common thought was that if 8-4 happened Miles would be canned.

Now let's apply those things to Crowton's contract situation:
He had two years remaining after the extension (this year and next) at $400,000 (minimum)

That would be $800,000 to buy him out. Next, we would have had to get another coordinator (probably $400,000 minimum), none of which would have come here with less than a three year contract. ($1,2000,000 minimum commitment.)

So let's say we did go 8-4 this year and Miles got fired, leaving a new coach to fill his own staff. That would have been a $2,000,000 (minimum) commitment for one year of a better offensive coordinator with terrible choices at quarterback. It's not really hard to see why those in charge would choose not to make that move with the highly likely (it seemed) possibility that this would be Miles' last season here.

I'm not saying I agree with it, only that I think that was the reason.