Having been a federal employee for 25 years I can tell you most (or at least some) government agencies go through stop-gap exercises of risk assessment and mitigation, contingency plans, disaster recovery, etc.
Are they useful? In my experience, not really, and it is not due to lack of effort necessarily.... Tons of funding and resources are required to do it effectively, most agencies aren't willing to make that kind of commitment....and that is at the federal government level, where they are supposed to be setting the example....I have to believe large corporations are much much worse at it....