I'm still holding out hope that Cal is simply evaluating O'Brien similar to how Jeff Lurie evaluated Chip Kelly. If it works, O'Brien can shout, "I told you so" to his critics. If it doesn't work, Cal can say, "he bought into O'Brien's vision and gave him full control and every opportunity to bring a championship to Houston".
Here are some interesting quotes after Lurie fired Kelly with two years on his contract and one year after giving him control of personnel.
"During the offseason, Lurie explained his decision to give Kelly the de facto role of general manager by saying that Kelly had a vision of how to get the Eagles to go from good to great. Instead, they went backwards."
"Lurie, at least, might have learned an important lesson. Bill Parcells' famous quote about wanting to shop for the groceries if he has to cook the meal remains a classic explanation of why coaches crave the power to shape a roster that, ultimately, decides their fate. But for the Eagles, Kelly was such a bad shopper, the ingredients never fit the recipe. Lurie apparently decided there was no saving it. Now, he's left to clean up the mess."
http://www.nfl.com/news/story/0ap3000000612251/article/jeffrey-luries-faith-in-chip-kelly-led-to-coachs-downfall