Well, yeah - using perfect 20/20 hindsight since he didn't know his base was going to stab him in his back, he should not have pulled Roberts as O'Connor's replacement. And, Julius Caesar should not have gone to the Senate that day . . . see, e.g. Law of Unintended Consequences. I hope, for all our sake, you are right.
Bush had total control over who he picked. Ceasar didn't have control over being stabbed or not.
Bush's pick was a bad one. If he had properly floated Miers and paid attention to the reaction, he would have never made the pick in the first place. That was his blunder and he and his advisers should know better.
I have to believe that either Bush is no longer listening to the advisers that got him elected. In fact, he may not be listening to any advisers at all beyond Andy Card and Laura Bush.