I do understand coaches being hyper defensive as the criticism comes very fast, there is no grace period these days. Win a championship, awesome, we love you. Miss a bowl game 9 months later, you suck, change it all. I get that that is quite the yo-yo of emotions.
With that said, you have to know that yo-yo has a lot to do with 3, 6, 8 million dollar salaries. You are paid incredible amounts in comparison, so when you are not producing/meeting expectations, it immediately feels like a whole lot is being wasted. When it reality, it is probably being wasted in the first place.