The Bush Administration prepared to fight a Beltway war for Pentagon modernization, not a global, multi-dimensional war. Rumsfeld loaded up with sophisticated Beltway Clerks like Paul Wolfowitz, etc — excellent choices for fighting Congress. 9/11 blindsided these best laid plans. Rumsfeld needed to clean house of the clerks and bring in warfighters.
I question the degree to which this could have been different, because I think that as a people our leadership is psychologically unready to do what it takes to win. As Ralph Peters (quoted in part by Colonel Bay) said:
In the bizarre political confusion of our times, with old party characterizations nearly meaningless, one crucial factor that shaped the Iraq effort went unnoticed: Neither party understands warfare, and neither party wants to.
Political correctness shaped the Bush administration's approach to military operations as decisively as it did the Clinton administration's pop-gun antics. The Bush bunch just did things on a larger scale - they wanted a war, but didn't want to hurt anybody.
No matter how many troops we send, we're bound to fail if the troops aren't allowed to fight. . .
(emphasis in underline in original as italics)