They don't retain staff. But the ones who retire or leave can generally get a very large contract when things like this pop up.

Until, of course, they are all gone. At which point the system will need to be rewritten by IBM, Oracle or some other useless, gigantic consulting firm.

Its tough to recruit for, so you really end up with folks who have job security for the forseeable future and others who become retired-in-place because of the rarity of cleared folks eligible to take on the post.