There have actually been a few major disasters in the past 10 years that have shown the value of good disaster recovery plans. Though they're far from perfect they do make a difference and can always be improved with newer techniques and technology.
When hurricane Katrina struck, I was working with the City of New York's network design team and we were tasked with creating an emergency refugee processing center for the thousands of hurricane victims that the city had taken in.
While we were able to throw this site together over a weekend by using a lot of manpower and equipment, it could have just as easily been done with a few decent virtual servers hosting the applications we needed. All applications including endpoints security could have been hosted virtually making design and deployment very simple. There most likely would have been significant cost savings on manpower, space, power, etc.
Though this is an extreme example it does show how virtual environments can be used for disaster recovery.