If you are the athletic director, after what season do you fire (or otherwise force out) Mack Brown.
The problem is that we know the problems started IMMEDIATELY post 2005, but there is no way he could have been fired before 2010 when everything had already cratered. And, while it would have been the right move, it also would have been EXTREMELY BALLSY to fire your head coach one year removed from a title game appearance.
And if you DON'T fire him then, it makes sense not to fire him after the 2011 season. And if you don't fire him THEN, then 2012 is tricky. If you fire him immediately after OU maybe everyone understands. But once you've finished the season strongly(ish) then inertia sets in. After all at this point you've bought in! You are implicated! Your fates are tied!*
And they can't fire him between 2005 and 2009, because even though we were slowly rotting on the inside we were winning and doing Texas stuff!
Is there anytime they could have fired him before 2005? After 2003, when we were blown out by OU and lost in the Holiday Bowl? Was this remotely an option?
Conclusion: It is simultaneously true that (A) everybody knows that Mack SHOULD have been fired already, and (B) it is unthinkable that Mack COULD have been fired already. Therefore, it was always impossible to avoid our currently shitty present and probably shitty future. Time is a wheel, and it is currently crushing us into dust and there's nothing we can do about it.