I agree he is completely replaceable. And there are a ton of options with just as much or more experience than Bronco had when he got the job. But unless Bronco decides not to renew his contract, resigns, or has a completely busted season in '15 - I think the job is his as long as he wants it.
And I hate to say it, but the timing is no bueno for a coaching overhaul. I am one of those fans that is holding out for a invite to the Big-XII - and the next couple years are crucial- Bronco needs to get his yewt together, because Independence is going to kill the program if we can't string together consistent 10 win seasons and top 25 finishes.