I have defended Coach Day for years, and I have never been the type to turn on a coach after a loss.
With that being said, I feel like the further from .500 we get in these big games, the more something is wrong. If all things were equal, we'd expect a coin flip, 50% win and loss. As athletes and coaches come and go, he remains the constant associated with not getting the job done. With each loss, we get further down the bell curve, and at some point we have to recognize that he plays some role in these losses...
Is it the preparation? The staff? Gameplan? Roster? Schemes? If he's not a direct cause, he has to be tangentially connected to the cause. It is his responsibility to find the breakdown and to fix it. He is a good coach, but it's on him to show that he can continue to grow and adapt as needed to put the team in a good position to win.