So the federal government is basically saying that you have to have a trusted 3rd party house your data.
		
		
	 
yes
	
	
		
		
			They trust that 3rd party to protect your data better than you in case of a disaster.
		
		
	 
Not really certain what their logic is behind the requirement  
		 
		
	 
Well, either way, your motive for using Iron Mountain is pretty clear.  I don't think federal mandate is the reason that most of their customers actually use their services though.  The motivation is that setting up your own facility and/or secure delivery mechanism is prohibitively expensive, and it makes more financial sense to put this in the hands of a 3rd party that specializes in this despite the fact it results in losing absolute control over your data.   Based on what the data is worth, how much risk is presented by trusting this 3rd party vs doing this yourself, and how much it would cost to avoid that risk.  The public cloud and the reasons companies are and will continue to adopt it aren't all that much different than this.   In an ideal world with all expenses spared would you rather have absolute control over your data?  Of course.  But that comes at an expense.  So the question is how much risk does trusting a 3rd party to do some of this present, and how much is the expense to avoid that risk?   The public cloud is going to come out on the plus side in this analysis more and more as the technology and companies delivering it continue to mature.
In the case of the end user it goes even beyond this.  They don't really want to have to worry about any of this stuff, security, technical specifications, all of that crap.   They simply want the computer to make their life easier and have us geeks worry about security and all of that on the back end - IT as a service, like their plumbing, electricity, television, and banking.  It's not all that surprising that bells and whistles are what sells them.  The public cloud has the promise to deliver this, along with a model that's inherently more secure than what they've been dealing with.