Why the DoD will not switch from SSN to random service numbers

Bruce Schneier:

We generally think of computer security as a problem of technology, but often systems fail because of misplaced economic incentives: the people who could protect a system are not the ones who suffer the costs of failure.

DoD will not suffer if my SSN is compromised and my identity is stolen. I do.

Unless the incentive can be turned on them, they have no reason to change.