To be more explicit, it isn't a guarantee as much as an implicit government economic policy which, it seems, boils down to:

It is the individual's responsibility for their own financial security, and the larger economic scheme of the United States should continue to support and encourage profiting off of moral hazards.

That said, there does seem to be some US consumer backlash, where individuals are basically attempting to stay out of this system altogether. Millennial house buying rates say it all: these rules are unfair, and the next generation don't want to play.