Dean's initial strategy was to win Iowa and New Hampshire big, then ride the wave of momentum. It worked ... but for Kerry, not Dean.
After New Hampshire, Dean decided to save his strength for Wisconsin, reasoning (as I said in a diary at the time) that it would take a couple weeks for the press to get tired of celebrating Kerry, and begin trying to tear him down -- and that doing well in Wisconsin would be enough momentum in itself to pose a credible challenge.
That strategy worked, too ... but for Edwards, not Dean.
"The scream" damaged Dean, but it didn't kill him. If he had figured out how to broaden his message, he could be where Edwards is now.
(Additional analysis at Needlenose.)