The $1 billion calculation probably considers not only damage in lost sales and lost time but the cost of dealing with a network intrusion multiplied by the number of affected systems. With confidential data almost certainly stored on a great number of those servers, a simple patch after the fact is not going to be enough... and if you can't guarantee a backdoor was not hidden somewhere, you're going to have to restore the entire system from a backup. That's going to cost a great deal of money at upwards a quarter million machines.
However, considering the patch has been available for six months, there is little hope the majority of those admins will bother to do anything more than apply the security update to cover the hole and not be bothered with it anymore. Security review? Subscribe to a security bulletin? Don't bother!
BugTraq, et al., should be mandatory reading for administrators of *any* networked computer. Period.
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